Apparatuses for end-to-end coordination of voice over cellular data network communications

ABSTRACT

Apparatuses of user equipment (UEs) for end-to-end coordination of voice over cellular data network communications. An apparatus of a UE includes one or more data storage devices and one or more processors. The one or more data storage devices are configured to store delay budget information pertaining to end-to-end delivery of a real-time transport protocol (RTP) stream sent from a remote UE to the UE. The one or more processors are configured to generate an application layer message including the delay budget information, the application layer message to be transmitted to the remote UE to enable the remote UE to request, from a cellular base station servicing the remote UE, additional air interface delay based on the delay budget information.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/115,228, filed Aug. 28, 2018, which claims priority to U.S.Provisional Patent Application No. 62/555,541, filed Sep. 7, 2017; U.S.Provisional Patent Application No. 62/569,348, filed Oct. 6, 2017; U.S.Provisional Patent Application No. 62/581,543, filed Nov. 3, 2017; andU.S. Provisional Patent Application No. 62/582,847, filed Nov. 7, 2017,the entire disclosures of all of which are hereby incorporated herein byreference.

BACKGROUND

Various embodiments generally may relate to the field of wirelesscommunications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a wireless communication systemillustrating a first UE shortening a connected mode DRX (CDRX) for adegraded VoLTE call.

FIG. 2 is a simplified illustration of an example FCI format of an RTCPfeedback message, according to some embodiments.

FIG. 3 is a simplified illustration of an example FCI format of an RTCPfeedback message, according to some embodiments.

FIG. 4 is a simplified illustration of a format of an example RTP headerextension message, according to some embodiments.

FIG. 5 is a simplified illustration of a format of an example RTP headerextension message, according to some embodiments.

FIG. 6 is a simplified end-to-end signal flow diagram of an exampleprocedure for an example scenario, according to some embodiments.

FIG. 7 is a simplified end-to-end signal flow diagram of an exampleprocedure, according to some embodiments.

FIG. 8 is a simplified end-to-end signal flow diagram of an exampleprocedure, according to some embodiments.

FIG. 9 is a simplified signal flow diagram illustrating a network-basedsolution to signal robustness information to eNBs in a wirelesscommunication system, according to some embodiments.

FIG. 10 is a simplified signal flow diagram illustrating a UE-basedsolution to signal robustness information to eNBs in a wirelesscommunication system, according to some embodiments.

FIG. 11 is a simplified illustration of a wireless communication system,according to some embodiments.

FIG. 12 is a simplified illustration of an example FCI format of an RTCPfeedback message, according to some embodiments.

FIG. 13 is a simplified illustration of an example FCI format of an RTCPfeedback message, according to some embodiments.

FIG. 14 is a simplified illustration of a format of an example RTPheader extension message, according to some embodiments.

FIG. 15 is a simplified illustration of a format of an example RTPheader extension message, according to some embodiments.

FIG. 16 is a simplified illustration of a format of an example RTPheader extension message, according to some embodiments.

FIG. 17 is a simplified signal flow diagram illustrating end-to-endapplication layer signaling of Max PLR in a wireless communicationsystem, according to some embodiments.

FIG. 18 illustrates an architecture of a system of a network inaccordance with some embodiments.

FIG. 19 illustrates an architecture of a system of a network inaccordance with some embodiments.

FIG. 20 illustrates example components of a device in accordance withsome embodiments.

FIG. 21 illustrates example interfaces of baseband circuitry inaccordance with some embodiments.

FIG. 22 is an illustration of a control plane protocol stack inaccordance with some embodiments.

FIG. 23 is an illustration of a user plane protocol stack in accordancewith some embodiments.

FIG. 24 illustrates components of a core network in accordance with someembodiments.

FIG. 25 is a block diagram illustrating components, according to someexample embodiments.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following detailed description refers to the accompanying drawings.The same reference numbers may be used in different drawings to identifythe same or similar elements. In the following description, for purposesof explanation and not limitation, specific details are set forth suchas particular structures, architectures, interfaces, techniques, etc. inorder to provide a thorough understanding of the various aspects ofvarious embodiments. However, it will be apparent to those skilled inthe art having the benefit of the present disclosure that the variousaspects of the various embodiments may be practiced in other examplesthat depart from these specific details. In certain instances,descriptions of well-known devices, circuits, and methods are omitted soas not to obscure the description of the various embodiments withunnecessary detail. For the purposes of the present document, the phrase“A or B” means (A), (B), or (A and B).

Release (Rel)-14 Work Addressing Radio Access Network (RAN)-Level DelayBudget Reporting

The radio access network 2 (RAN2)-led Release 14 (Rel-14) work item“Voice and Video Enhancement for [Long Term Evolution] [(LTE)]”(LTE_VoLTE_ViLTE_enh) specified several voice over long term evolution(LTE) and video over LTE (VoLTE/ViLTE) enhancement features includingradio access network (RAN) assisted codec adaptation, VoLTE/ViLTEsignalling optimization and VoLTE/ViLTE quality/coverage enhancement. InSA4, Rel-14 item “RAN-Assisted Codec Adaptation in MTSI”(LTE_VoLTE_ViLTE_enh-S4) was completed as a building block of theLTE_VoLTE_ViLTE_enh feature to specify media handling aspects ofRAN-assisted codec adaptation functionality in Third GenerationPartnership Project (3GPP) technical specification (TS) 26.114.

In addition to RAN-assisted codec adaptation, another important featurespecified by RAN2 as part of the LTE_VoLTE_ViLTE_enh feature is Voiceover LTE (VoLTE) quality/coverage enhancement functionality. As part ofthis functionality, RAN2 specifies a delay budget reporting framework sothat the VoLTE coverage can be effectively enhanced by relaxing the airinterface delay budget. The UE uses radio resource control (RRC)signalling to report the delay budget information. Based on the reporteddelay budget information, when a user equipment (UE) is in goodcoverage, a cellular base station (e.g., an evolved NodeB, or “eNB”) canconfigure longer Discontinuous Reception (DRX) for power saving purposesor the eNB can reduce DRX cycle in order to help the remote UE andreduce end-to-end delay and jitter, since when the remote UE is in badcoverage, the local eNB of that remote UE can increase theretransmission times in order to reduce the packet loss.

Use Case for RAN Delay Budget Reporting

FIG. 1 is a simplified block diagram of a wireless communication system100 illustrating a first UE 110 shortening a connected mode DRX (CDRX)for a degraded VoLTE call. The wireless communication system 100includes the first UE 110 (sometimes referred to herein as “UE1” 110), asecond UE 120 (sometimes referred to herein as “UE2” 120), a first eNB130 (sometimes referred to herein as “eNB1” 130), a second eNB 140(sometimes referred to herein as “eNB2” 140), and a core network 150.The first eNB 130 is configured to service the first UE 110, and thesecond eNB 140 is configured to service the second UE 120.

In one example operational scenario, a wireless communication link 115between UE1 110 and eNB1 130 may be in a relatively good radio conditionand therefore originally configured by eNB1 130 with 40 milliseconds(ms) CDRX. In contrast, a wireless communication link 125 between UE2120 and eNB2 140 may be in a relatively poor radio condition andtherefore originally configured by eNB2 140 with no CDRX. This exampleoperational scenario may result in the following operations:

-   -   UE2 120 detects the poor radio condition of the wireless        communication link 125 (e.g., high block error ratio (BLER)). As        a result, UE2 120 may perform many hybrid automatic repeat        request (HARQ) retransmissions, which causes long jitter and        end-to-end delay at the receiver UE1 110.    -   UE1 110 detects that the VoLTE quality is poor (e.g., large        jitter or delay). As a result, UE1 110 suggests to eNB1 130 to        de-configure CDRX or shorten CDRX cycle. As a result, the        end-to-end delay and jitter are reduced.    -   UE2 120 detects that the VoLTE end-to-end delay has dropped. As        a result, UE2 120 reports a larger delay headroom to eNB2 140,        so eNB2 140 may apply more enhanced machine-type-communications        (eMTC) repetitions (or more HARQ retransmissions), which may        result in increased jitter or delay. This lack of coordination        between UE1 110 and UE2 120 may thus create a tug of war between        the UE1 110 and the UE2 120.

One solution is to configure UE1 110 to indicate to eNB1 130 a CDRXcycle value that is different from the configured CDRX cycle value. UE1110 indicates a preferred CDRX cycle length via a new RRC message. TheeNB1 130 decides which CDRX cycle to use. A prohibit timer is configuredby eNB1 130 to prevent UE1 110 from sending the indication toofrequently.

Signaling Solution in 3GPP TS 36.331 on RAN Delay Budget Reporting

In order to realize the solution above, RAN2 has adopted the followingRRC signaling in TS 36.331 based on the UEAssistanceInformation messagewith the semantics shown in Table 1 below, which allows UE1 110 tosignal to eNB1 130 delay budget reporting information as follows:

A UE in good coverage indicates a preference to the eNB to reduce thelocal air interface delay by sending a UEAssistanceInformation messagewith delayBudgetReport value and indication of type1 to decrease theconnected mode DRX cycle length, so that the E2E delay and jitter can bereduced.

The peer UE in bad coverage can send a UEAssistanceInformation messagewith delayBudgetReport value and indication of type2 to its eNB toindicate a preference on Uu air interface delay adjustments

When the UE detects changes such as end-to-end multimedia telephonyservice for Internet Protocol (IP) multimedia core network subsystem(IMS) (MTSI) voice quality or local radio quality, the UE may inform theeNB its new preference by sending a UEAssistanceInformation message withupdated contents on delayBudgetReport.

TABLE 1 Semantics of the UEAssistanceInformation message for RAN delaybudget reporting UEAssistanceInformation field descriptionsdelayBudgetReport Indicates the UE-preferred adjustment to connectedmode DRX or coverage enhancement configuration. type1 Indicates thepreferred amount of increment/decrement to the connected mode DRX cyclelength with respect to the current configuration. Value in number ofmilliseconds. Value ms40 corresponds to 40 milliseconds, msMinus40corresponds to −40 milliseconds and so on. type2 Indicates the preferredamount of increment/decrement to the coverage enhancement configurationwith respect to the current configuration so that the Uu air interfacedelay changes by the indicated amount. Value in number of milliseconds.Value ms24 corresponds to 24 milliseconds, msMinus24 corresponds to −24milliseconds and so on.Application Layer Signaling of Delay Budget Information

While RAN-layer delay budget reporting allows UEs to locally adjust airinterface delay, such a mechanism does not provide coordination betweenthe UEs to manage delay and jitter on an end-to-end basis. To alleviatethis problem, the following real-time transport protocol/real-timetransport control protocol (RTP/RTCP) signaling may be defined to signaldelay budget information between UEs.

-   -   A new RTCP feedback (FB) message type to carry available        additional delay budget information during the RTP streaming of        media (signalled from the MTSI receiver to the MTSI sender);    -   A new Session Description Protocol (SDP) parameter on the        RTCP-based ability to signal available additional delay budget        information during the IMS/session information protocol (SIP)        based capability negotiations;    -   A new RTP header extension type to carry query signal for        available additional delay budget information during the RTP        streaming of media (signalled from the MTSI sender to the MTSI        receiver);    -   A new SDP parameter on the RTP-based ability to signal RAN-level        bitrate recommendation info during the IMS/SIP-based capability        negotiations.

RTCP feedback messages signalled from the MTSI receiver to the MTSIsender may also carry available delay budget information for the reverselink (i.e., for the sent RTP stream). In this case, the use of RTPheader extension messages may not be necessary.

RTP header extension messages signalled from the MTSI sender to the MTSIreceiver may also carry available delay budget information for thereverse link (i.e., for the received RTP stream). In this case, the useof RTCP feedback messages may not be necessary.

The signaling of available additional delay budget information may useRTCP feedback messages as specified in Internet Engineering Task Force(IETF) 4585. As such, the RTCP feedback message is sent from the MTSIreceiver to the MTSI sender to convey to the sender about the availableadditional delay budget information from the perspective of thereceiver. The recipient UE (MTSI sender) of the RTCP feedback messagemay then use this information in determining how much delay budget itmay request from its eNB over the RAN interface, e.g. by using RRCsignalling based on UEAssistanceInformation.

The RTCP feedback message is identified by payload type (PT)=PSFB (206),where PSFB refers to a payload-specific feedback message. Feedbackmessage type (FMT) shall be set to the value “Y” for availableadditional delay budget information. The RTCP feedback method mayinvolve signaling of available additional delay budget information inboth of the immediate feedback and early RTCP modes.

Feedback control information (FCI) format can be as follows. In someembodiments, the FCI 200 can contain exactly one instance of theavailable additional delay budget information, including one or more ofthe following parameters (available additional delay parameter ismandatory, but others are optional and may not be present):

-   -   Available additional delay parameter (e.g., specified in        milliseconds using, for example, 16 bits)    -   Sign “s” for the additional delay parameter, and whether this is        positive or negative (e.g., specified as a Boolean (1 bit)        (optional parameter))    -   Query “q” for additional delay budget (e.g., specified as a        Boolean (1 bit) (optional parameter))

The sign of the available additional delay parameter may be positive ornegative (e.g., as indicated by sign “s”). In some embodiments, when theavailable additional delay parameter takes a positive value, the UEindicates that there is additional delay available. In case theadditional delay parameter takes a negative value, the UE indicates thatthe delay budget has been reduced. As such, a sequence of RTCP feedbackmessages may be sent by the UE to report on the additional delay budgetavailability in increments.

The query “q” is to request information regarding additional delaybudget for the reverse link (for which the originator of the RTCPfeedback message is the voice sender). This is an alternative to the RTPheader extension signalling method described below. When the MTSIreceiver sends RTCP feedback messages addressing the available delaybudget for the received RTP stream, the query parameter is not to beincluded or is to be set to ‘0’. When query parameter is included andset to ‘1’, the purpose of the RTCP feedback message is to ask foradditional delay budget for the reverse link (i.e., for the sent RTPstream). This is an alternate to the RTP header extension signallingmethod described below. This signalling option, however, relies on thepresence of a bi-directional link (i.e., it would not work in case ofsend-only or receive-only streams). When the query bit is set to ‘1’,the delay budget value delay may be interpreted as the additional delaybudget requested by the sender of the RTCP feedback message (i.e., MTSIreceiver) for the reverse link (i.e., sent RTP stream).

It should be noted that this FCI format is for illustration purposes,and other formats can also be defined to convey available additionaldelay budget information.

FIG. 2 is a simplified illustration of an example FCI format of an RTCPfeedback message 200 (sometimes referred to as “RTCP-FB” 200), accordingto some embodiments. The FCI of the RTCP feedback message 200 includesan available additional delay parameter 260, a sign “s” 280 (i.e., thesingle-bit message indicating the sign of the available additional delayparameter), and zero padding 270. The RTCP feedback message 200 does notinclude the query signal “q.”

In the example illustrated by FIG. 2 the high byte should be followed bythe low byte, where the low byte holds the least significant bits.

FIG. 3 is a simplified illustration of an example FCI format of an RTCPfeedback message 300, according to some embodiments. The FCI of the RTCPfeedback message 300 includes an available additional delay parameter360, a sign “s” 380, and zero padding 370, similar to the additionaldelay parameter 260, the sign “s” 280, and the zero padding 270 of FIG.2. The FCI format of the RTCP feedback message 300, however, includes aquery signal “q” 390 (“q” stands for the single-bit message on query).

A 3GPP MTSI client (based on TS 26.114) supporting this RTCP feedbackmessage 300 can offer such capability in the SDP for all media streamscontaining video and/or audio. The offer can be made by including ana=RTCP feedback (a=rtcp-fb) attribute in conjunction with the followingparameter: 3gpp-delay-budget. A wildcard payload type (“*”) may be usedto indicate that the RTCP feedback attribute applies to all payloadtypes. An example usage of this attribute is as follows:

-   -   a=rtcp-fb:* 3gpp-delay-budget

An augmented ABNF for rtcp-fb-val corresponding to the feedback type“3gpp-delay-budget” can be given as follows:

-   -   rtcp-fb-val=/“3gpp-delay-budget”        The term “ABNF” may refer to an Augmented Backus-Naur Form,        which is a meta-language with its own formal syntax and rules        based on the Backus-Naur Form and is used to define message        exchanges in a bi-directional communications protocol.

FIG. 4 is a simplified illustration of a format of an example RTP headerextension message 400, according to some embodiments. In some settings,the query for available additional delay budget information may besignaled by the MTSI sender as part of the transmitted RTP stream usingthe RTP header extension message. As illustrated in FIG. 4, the exampleRTP header extension message 400 includes an ID 462, a len=7 464, aquery “q” 490, and zero padding 470.

FIG. 5 is a simplified illustration of a format of an example RTP headerextension message 500, according to some embodiments. In the exampleformat shown in FIG. 5 the query from the MTSI sender may also containthe additional delay budget requested. The example RTP header extensionmessage 500 includes an ID 562, a len=7 564, a query “q” 590, anavailable additional delay parameter delay 560, a sign “s” 580 of theavailable additional delay parameter delay 560, and zero padding 570.Similarly as discussed above with reference to FIG. 2, the requestedadditional delay budget delay 560 may be specified in milliseconds (16bits), and the sign “s” 580 is for the additional delay budget delay 560and whether this is positive or negative may be specified as a Boolean(1 bit) (optional parameter)

When the MTSI sender signals RTP header extension messages addressingthe requested delay budget for the sent RTP stream, the query parameteris always to be included and set to ‘1’. When query parameter is notincluded or set to ‘0’, the purpose of the RTP header extension messageis to indicate the available additional delay budget for the reverselink (i.e., for the received RTP stream). This is an alternate to theRTCP feedback message signalling method described above. This signallingoption, however, relies on the presence of a bi-directional link (i.e.,it would not work in case of send-only or receive-only streams). Whenthe query bit is omitted or set to ‘0’, the delay budget value delay maybe interpreted as the available additional delay budget indicated by theMTSI sender for the reverse link (i.e., received RTP stream).

A 3GPP MTSI client (based on TS 26.114) supporting this RTP headerextension message can offer such capability in the SDP for all mediastreams containing video/audio. This capability can be offered byincluding the a=extmap attribute indicating a dedicated uniform resourcename (URN) under the relevant media line scope. The URN corresponding tothe capability to signal query for available additional delay budgetinformation is: urn:3gpp:delay-budget-query. An example of usage of thisURN in the SDP is as follows:

-   -   a=extmap:7 urn:3gpp:delay-budget-query        The number 7 (len=7) in the examples of FIGS. 4 and 5 may be        replaced with any number in the range 1-14.

Example End-to-End Signaling Flows

FIGS. 6-8 illustrate signal flow diagrams of example procedures inexample scenarios that fall within the scope of the disclosure. Each ofFIGS. 6-8 includes a request message 602. The request message 602 ofFIGS. 6-8 is a generalized application level rate request message thatcorresponds to codec mode request (CMR) or RTCP-APP (application) forvoice.

FIG. 6 is a simplified end-to-end signal flow diagram of an exampleprocedure for an example scenario, according to some embodiments. Theprocedure of FIG. 6 describes end-to-end RAN delay budget reportingusage for voice in a wireless communication system 600. The wirelesscommunication system 600 includes a first UE 610 (sometimes referred toherein as “UE1” 610), a second UE 620 (sometimes referred to herein as“UE2” 620), a first eNB 630 (sometimes referred to herein as “eNB1”630), a second eNB 640 (sometimes referred to herein as “eNB2” 640), afirst evolved packet core (EPC) 652, a second EPC 654, and an IMS 656.For purposes of FIG. 6, the first eNB 630 is servicing the first UE 610and the second eNB 640 is servicing the second UE 620.

In operation, UE1 610 sends, to UE2 620, a request message 602 includinga rate request via CMR or RTCP-APP for voice at bitrate R0. UE2 620sends, to UE1 610, an RTP media flow 604 for voice with bitrate R0. UE1610 detects 606 that there is long end-to-end delay and jitter by, forexample, detecting high packet losses despite applying the highestpossible jitter buffer (subject to the jitter buffer management (JBM)compliance requirement of MTSI) and/or by monitoring RTCP sender andreceiver reports). In the meantime, UE1 610 detects 608 good radioconditions locally, e.g., eNB1 630 sends a downlink (DL) access networkbitrate recommendation (ANBR) 612 of bitrate R1>R0 to UE1 610, and UE1610 measures low block error rate (BLER) over the local radio linkbetween UE1 610 and eNB1 630. Hence, UE1 610 concludes that UE2's localradio conditions are poor. UE1 610 sends a UEAssistanceInformationmessage to eNB1 630 with type-1 to request 614 that eNB1 630 turn offCDRX. The first eNB 630 grants this request 614 and turns off CDRX forUE1 610, and transmits an acknowledgment 616 to UE1 610 acknowledgingthat CDRX is turned off.

UE1 610 sends an RTCP-FB message 618 to UE2 620 indicating theavailability of additional delay budget availability. A concrete delaynumber may be reported by the RTCP-FB message 618 that also may bedetermined considering JBM constraints of UE1 610 and can be based on anassessment by UE1 610 of how much additional delay UE1 610 can tolerate.UE1 610 may send a sequence of RTCP-FB messages 618 in this fashion toincrementally report about the additional delay budget availability. Insome embodiments, the reported delay number in some RTCP-FB messages 618may be negative if UE1 610 cannot tolerate further delay or wishes toreduce the delay. UE2 620 requests 624 additional delay budget from eNB2640 in order to perform additional re-transmissions to increase thereliability of its uplink (UL) transmissions. The second eNB 640 grantsand acknowledges 626 this request 624. UE1 610 measures 628 reducedend-to-end delay and jitter, and packet losses are also reduced. UE2 620sends, to UE1 610, an RTP media flow 632 for voice with bitrate R0.

In the example of FIG. 6 the available delay budget may be computed byUE1 610 (MTSI receiver) based on network delay, jitter, packet loss rate(PLR) and potentially other parameters. It may also take into account aconstraint on the way jitter buffer management (JBM) is performed. Inthis respect, the following should be noted regarding the expected UEbehavior:

-   -   Allowing UE2 620 to use more retransmission will likely increase        the jitter. This potentially causes more packets to be dropped        at the JBM for UE1 610.    -   On the other hand, more retransmission also allows UE2 620 to        reduce packet losses in its RAN and this means more end-to-end        reliability. So a fine balance between increased jitter and more        retransmission should be struck here.    -   It is up to UE1 610 to grant any additional delay budget. If UE1        610 thinks that it is already close to its JBM constraint and        cannot tolerate any additional delay (as this would lead to more        packets being dropped), it would not signal additional delay        availability to UE2 620 (e.g., in the RTCP-FB message 622).

Once UE2 620 goes into good coverage, the packet losses seen by UE1 610will be reduced and UE2 620 will also no longer need the additionaldelay budget. In this case, either UE1 610 would reduce the availabledelay budget or UE2 620 would request that its delay budget be reduced;both types of signaling are possible within the scope of the disclosure(e.g., via indication of negative delay values in the RTCP-FB message618). It should also be noted that UE1 610 is not the asker but thegrantor in this framework, and it is UE2 620 that requests any changes.UE1 610 would grant or disapprove requests from UE2 620.

FIG. 7 is a simplified end-to-end signal flow diagram of an exampleprocedure, according to some embodiments. FIG. 7 is the same as FIG. 6with the addition that UE1 610 transmits a rate request 734 to UE2 620.For example, in the situation where UE1 610 still suffers from highpacket loss and measures high end-to-end delay and jitter, UE1 610sends, to UE2 620, the rate request 734 via CMR or RTCP-APP for voice atbitrate R2<R0. Other kinds of adaptations may also be invoked. Forexample, application layer redundancy may be used in case the receiverside detects major packet loss but delay and jitter are within desiredbounds.

FIG. 8 is a simplified end-to-end signal flow diagram of an exampleprocedure, according to some embodiments. The example procedure depictedby FIG. 8 is a variant of the procedure of FIG. 6. FIG. 8 is the same asFIG. 6 except where UE2 620 requests additional delay budget from UE1610 during the media flow (e.g., using an RTP header message 838) afterhaving detected 836 poor radio conditions (e.g., high BLER) over thelocal RAN. The presence of this request message 838 may further informUE1 610 that the radio conditions on the side of UE2 620 are poor (inaddition to its own detection based on end-to-end delay and jittermeasurements).

Examples A

The following is a non-exhaustive list of example embodiments that fallwithin the scope of the disclosure. In order to avoid complexity inproviding the disclosure, not all of the examples listed below areseparately and explicitly disclosed as having been contemplated hereinas combinable with all of the others of the examples listed below andother embodiments disclosed hereinabove. Unless one of ordinary skill inthe art would understand that these examples listed below, the list ofexamples of Examples B below, and the above and below disclosedembodiments, are not combinable, it is contemplated within the scope ofthe disclosure that such examples and embodiments are combinable.

Example 1 may include local user equipment (UE) operable to performmultimedia telephony with a remote UE, the local UE having one or moreprocessors configured to: communicate, from the local UE to the remoteUE, the available additional delay budget information via a real-timetransport control protocol (RTCP) feedback message, where the availableadditional delay budget pertains to end-to-end delivery of the RTPstream from the remote UE to the local UE. Based on the signaledadditional delay information, the remote UE requests from its local eNBadditional air interface delay to improve its transmissions.

Example 2 may include the local UE of Example 1 or some other exampleherein, wherein prior to sending the RTCP feedback message containingthe additional delay budget information, the local UE receives a querymessage from the remote UE in an RTP header extension message containingadditional delay budget request information.

Example 3 may include the local UE of Example 1 or some other exampleherein, wherein the one or more processors are further configured toreceive a session description protocol (SDP) offer message from theremote UE that includes an RTCP feedback attribute that is associatedwith a Third Generation Partnership Project (3GPP) 3gpp-delay-budgetparameter, thereby indicating that the remote UE supports the receptionof available delay budget information signaled via RTCP feedbackmessages.

Example 4 may include the local UE of Example 1 or some other exampleherein, wherein the one or more processors are further configured tosend a session description protocol (SDP) answer message to the remoteUE that includes an RTCP feedback attribute that is associated with aThird Generation Partnership Project (3GPP) 3gpp-delay-budget parameter,thereby acknowledging that the local UE supports the transmission ofavailable delay budget information signaled via RTCP feedback messages.

Example 5 may include the local UE of Example 2 or some other exampleherein, wherein the one or more processors are further configured toreceive a session description protocol (SDP) offer message from theremote UE that includes an extension map attribute that is associatedwith a Third Generation Partnership Project (3GPP) delay-budget-queryparameter, thereby indicating that the remote UE supports query withadditional delay budget request information signaled via RTP headerextension messages.

Example 6 may include the local UE of Example 2 or some other exampleherein, wherein the one or more processors are further configured tosend a session description protocol (SDP) answer message to the remoteUE that includes an extension map attribute that is associated with aThird Generation Partnership Project (3GPP) delay-budget-queryparameter, thereby acknowledging that the local UE supports query withadditional delay budget request information signaled via RTP headerextension messages.

Example 7 may include the local UE of Example 1 or some other exampleherein, wherein the RTCP feedback message communicated from the local UEto the remote UE includes a descriptor that contains additional delaybudget information with the following values: relative additional delayvalue, sign of the delay parameter (positive or negative), queryparameter for the delay over the reverse link.

Example 8 may include the local UE of Example 2 or some other exampleherein, wherein the RTP header extension received from the remote UEincludes a descriptor that contains the requested additional delaybudget information with the following query values: the requestedadditional delay value, sign of the delay parameter (positive ornegative).

Example 9 may include the local UE of Example 1 or some other exampleherein, wherein the additional delay budget information is determinedbased on an assessment of how much additional delay the UE can toleratebased on end-to-end monitoring of network delay, Jitter, packet lossrate (PLR), as well as consideration of the constraints of the jitterbuffer management in the UE.

Example 10 may include the local UE of Example 1 or some other exampleherein, wherein the local UE detects high end-to-end packet loss, delayand/or jitter while also detects good radio conditions locally (e.g., bydetecting low block error rate (BLER) in its RAN and/or receiving a highenough bitrate recommendation from its RAN) and sends a request to itslocal eNB to reduce air interface delay, e.g., by turning off cRDX.

Example 11 may include the local UE of Example 9 or some other exampleherein, wherein the additional available delay budget signaled by thelocal UE to the remote UE using RTCP feedback messages contains therelative additional delay value that corresponds to the air interfacedelay reduction achieved (e.g., through turning off cDRX) after thecommunication with the eNB.

Example 12 may include the local UE of Example 1 or some other exampleherein, wherein the air interface delay increase requested by the remoteUE from its eNB corresponds to the additional delay budget signaled fromthe local UE to the remote UE using the RTCP feedback message.

Example 13

An apparatus of a user equipment (UE), comprising: one or more datastorage devices to store delay budget information pertaining toend-to-end delivery of a real-time transport protocol (RTP) stream sentfrom a remote UE to the UE; and one or more processors to generate anapplication layer message including the delay budget information, theapplication layer message to be transmitted to the remote UE to enablethe remote UE to request, from a cellular base station servicing theremote UE, additional air interface delay based on the delay budgetinformation.

Example 14

The apparatus of Example 13, wherein the application layer messagecomprises a real-time transport control protocol (RTCP) feedback messageincluding the delay budget information.

Example 15

The apparatus of Example 14, wherein the application layer message isconfigured to indicate a relative additional delay value, a sign of therelative additional delay value, and a Boolean query parameter, which,if set to positive, allows requesting delay for a reverse RTP streamsent from the UE to the remote UE, the sign of the relative additionaldelay value indicating whether the relative additional delay valueshould be added to the delay budget or whether the delay budget shouldbe reduced by the relative additional delay value.

Example 16

The apparatus of Example 13, wherein the application layer messagecomprises an RTP header extension message including the delay budgetinformation, which is sent as part of a reverse RTP stream from the UEto the remote UE.

Example 17

The apparatus of Example 16, wherein the application layer message isconfigured to indicate a relative additional delay value, a sign of therelative additional delay value, and a Boolean query parameter, theBoolean query parameter being set to positive to enable requesting delayfor a reverse RTP stream sent from the UE to the remote UE, the sign ofthe relative additional delay value indicating whether the relativeadditional delay value should be added to the delay budget or whetherthe delay budget should be reduced by the relative additional delayvalue.

Example 18

The apparatus according to any one of Examples 13-17, wherein the one ormore processors are configured to decode a query message received fromthe remote UE before transmission of the application layer message tothe remote UE, the query message including additional delay budgetrequest information requesting the delay budget information from the UE.

Example 19

The apparatus of Example 18, wherein the one or more processors arefurther configured to decode a session description protocol (SDP) answermessage received from the remote UE, the SDP answer message including anextension map attribute that is associated with a standardized delaybudget query parameter, the standardized delay budget query parameterconfigured to indicate that the remote UE supports query with theadditional delay budget request information signaled via applicationlayer messages.

Example 20

The apparatus according to any one of Examples 18 and 19, wherein theone or more processors are further configured to generate a sessiondescription protocol (SDP) answer message to be transmitted to theremote UE, the SDP answer message including an extension map attributethat is associated with a standardized delay budget query parameterconfigured to acknowledge that the UE supports query with the additionaldelay budget request information signaled via application layermessages.

Example 21

The apparatus according to any one of Examples 18-20, wherein the querymessage received from the remote UE includes a requested additionaldelay value and a sign of the additional delay value, the sign of theadditional delay value indicating whether the additional delay valueshould be added to the delay budget or whether the delay budget shouldbe reduced by the additional delay value.

Example 22

The apparatus according to any one of Example 13-21, wherein the one ormore processors are further configured to decode a session descriptionprotocol (SDP) offer message received from the remote UE, the SDP offermessage configured to indicate that the remote UE supports reception ofthe delay budget information via application layer messages.

Example 23

The apparatus according to any one of Examples 13-22, wherein the one ormore processors are further configured to generate a session descriptionprotocol (SDP) answer message to be transmitted to the remote UE, theSDP answer message configured to indicate that the UE supportstransmission of the delay budget information via application layermessages.

Example 24

The apparatus according to any one of Examples 13-23, wherein the one ormore processors are further configured to determine the delay budgetinformation based on an assessment of how much additional delay the UEcan tolerate based on end-to-end monitoring of network delay, jitter,packet loss ratio (PLR), and constraints for a jitter buffer manager ofthe UE.

Example 25

The apparatus according to any one of Examples 13-24, wherein the one ormore processors are further configured to generate, responsive todetections of high end-to-end packet loss and good local radioconditions between the UE and a cellular base station servicing the UE,a request message to be transmitted to the eNB servicing the UE, therequest message configured to request that the cellular base stationservicing the UE reduce the air interface delay.

Example 26

The apparatus of Example 25, wherein the delay budget information of theapplication layer message includes a relative additional delay valueconfigured to indicate an air interface delay reduction achievedresponsive to the cellular base station servicing the UE reducing theair interface delay.

Example 27

The apparatus according to any one of Examples 13-26, wherein theadditional air interface delay requested by the remote UE is equal to anadditional delay budget signaled from the UE to the remote UE using theapplication layer message.

Example 28

An apparatus of a user equipment (UE), comprising: one or more datastorage devices to store delay budget information pertaining toend-to-end delivery of a real-time transport protocol (RTP) stream sentfrom a remote UE to the UE; and one or more processors to generate areal-time transport control protocol (RTCP) feedback message to transmitto the remote UE, the RTCP feedback message including the delay budgetinformation, the RTCP feedback message to be transmitted to the remoteUE to enable the remote UE to request, from a cellular base stationservicing the remote UE, additional air interface delay based on thedelay budget information.

Example 29

The apparatus of Example 28, wherein the one or more processors arefurther configured to decode a query message received in an RTP headerextension message in the RTP stream sent from the remote UE beforetransmission of the RTCP feedback message to the remote UE, the querymessage including additional delay budget request information requestingthe delay budget information from the UE.

Example 30

An apparatus of a user equipment (UE), comprising: one or more datastorage devices to store delay budget information pertaining toend-to-end delivery of a real-time transport protocol (RTP) stream froma remote UE to the UE; and one or more processors to generate an RTPheader extension message including the delay budget information, the RTPheader extension message to be transmitted to the remote UE to enablethe remote UE as part of a reverse RTP stream sent to the remote UE torequest, from a cellular base station servicing the remote UE,additional air interface delay based on the delay budget information.

Example 31

The apparatus of Example 30, wherein the RTP header extension message isconfigured to indicate a relative additional delay value, a sign of therelative additional delay value, and a Boolean query parameter, which,if set to positive allows requesting delay for a reverse RTP stream sentfrom the UE to the remote UE, the sign of the relative additional delayvalue indicating whether the relative additional delay value should beadded to the delay budget or whether the delay budget should be reducedby the relative additional delay value.

Example 32 may include an apparatus comprising means to perform one ormore elements of a method described in or related to any of Examples1-31, or any other method or process described herein.

Example 33 may include one or more non-transitory computer-readablemedia comprising instructions to cause an electronic device, uponexecution of the instructions by one or more processors of theelectronic device, to perform one or more elements of a method describedin or related to any of Examples 1-31, or any other method or processdescribed herein.

Example 34 may include an apparatus comprising logic, modules, orcircuitry to perform one or more elements of a method described in orrelated to any of Examples 1-31, or any other method or processdescribed herein.

Example 35 may include a method, technique, or process as described inor related to any of Examples 1-31, or portions or parts thereof.

Example 36 may include an apparatus comprising: one or more processorsand one or more computer readable media comprising instructions that,when executed by the one or more processors, cause the one or moreprocessors to perform the method, techniques, or process as described inor related to any of Examples 1-31, or portions thereof.

Example 37 may include a signal as described in or related to any ofExamples 1-31, or portions or parts thereof.

Example 38 may include a signal in a wireless network as shown anddescribed herein.

Example 39 may include a method of communicating in a wireless networkas shown and described herein.

Example 40 may include a system for providing wireless communication asshown and described herein.

Example 41 may include a device for providing wireless communication asshown and described herein.

Maximum Packet Loss Ratio Information Signaling for Single Radio VoiceCall Continuity (SRVCC) Handover Optimization

Embodiments herein may enable application-layer mechanisms to signalmaximum packet loss ratio (Max PLR) information toward enabling SingleRadio Voice Call Continuity (SRVCC) handover optimization for Voice overLong Term Evolution (VoLTE) calls. Embodiments may take into account theimpact of proprietary client implementations of Packet-Loss Concealment(PLC) and Jitter Buffer Management (JBM) on having different Max PLR andpotential mechanisms to indicate this to the network.

In addition to the negotiated codecs and codec modes, the end-to-endquality and robustness of the VoLTE connection also depend on UEcapabilities including, for example, JBM and PLC. In the meantime, a MaxPLR parameter is derived by Policy and Charging Rules Function (PCRF)(e.g., in the network-based architecture) or the UE and signaled to thecellular base station (e.g., eNB). This Max PLR parameter does notcapture the impact of such UE capabilities. As such, further refinementson Max PLR could be considered on a per UE basis depending on thecapabilities of the UE. The JBM and PLC capabilities of the UE, however,are not accounted for in previous solutions and resulting SRVCC handoveroptimizations are not realized.

According to various embodiments disclosed herein, Real-Time TransportProtocol (RTP)/RTP Control Protocol (RTCP)-based mechanisms may bedefined to enable end-to-end signaling of maximum packet loss ratio(PLR) information for enabling SRVCC handover optimization. Theembodiments disclosed herein may provide better management of SRVCChandover decisions at the eNB and therefore improve end-to-end qualityof VoLTE calls.

Release-15 Work Addressing EVOLP (Enhanced VoLTE Performance)

It may be important to maintain voice quality on Long Term Evolution(LTE) as high as possible. Maintaining high voice quality may avoid orat least delay SRVCC as much as possible. Avoiding or delaying SRVCC mayminimize the negative impact on user experience for VoLTE subscribers inareas with weak LTE coverage.

Some RAN implementations may not have sufficient information (e.g.,codec configuration information) to perform optimized handover forVoLTE. Consequently, a VoLTE call could be unnecessarily handed over toSecond Generation (2G) and/or Third Generation (3G) circuit-switched(CS) networks via SRVCC handover (HO) even though the VoLTE call cansurvive LTE weak coverage.

The information needed by the RAN to make optimized HO decisions forVoLTE, from an architecture point of view, may be identified. It mayalso be determined how to provide the RAN with this information. ARelease 15 (Rel-15) eVoLP study item was completed to address thisproblem. 3GPP technical reference (TR) 23.759 was developed. The term“eVoLP” refers to “enhanced Voice over Internet Protocol” or “enhancedVoLTE performance.”

Increased robustness of speech calls (as in technical specification (TS)26.114) is enabled by selection of codecs and their configuration,in-call dynamic rate and mode adaptation, and perhaps application layerfull redundancy. Enhanced Voice Services (EVS), especially the EVSChannel Aware mode, demonstrate higher robustness against transmissionerrors than Adaptive Multi-Rate (AMR) and AMR-wideband (AMR-WB) codecsby encoding packets with partial redundancy.

A “Max PLR” parameter was determined to be used (maximum tolerablepacket loss rate) to inform the eNB about the robustness of the selectedcodec. The robustness (e.g., Max PLR) information can be conveyed to theeNB using either the signaling from the network (PCRF) or signaling fromthe UE. The eNB can derive the related SRVCC thresholds (implementationdependent) from the Max PLR. In case of multi-rate/multi-mode codecconfigurations, different codec modes have, in general, different MaxPLRs (e.g., different robustness) associated therewith.

The robustness (i.e., Max PLR) information can be conveyed to the eNBusing either signaling from the network (PCRF) or signaling from the UE.

Network-Based Architecture Embodiments

The network-based architecture embodiments may rely on the fact that theinformation on the negotiated codecs and configurations (or codec modes)for the session is available in the PCRF through its knowledge of theSession Description Protocol (SDP) that contains the negotiated sessionparameters. Based on such information, the PCRF can derive the relevantrobustness parameter information (e.g., Maximum Packet Loss Rate) andsignal this information to the eNB. The derivation of the robustnessparameter information based on the negotiated codec modes can beperformed subject to a standardized mapping rule (e.g., with anindication of packet loss rate for each codec mode and calculation ofthe Maximum Packet Loss Rate based on the negotiated codec modes). Anexample of the network-based architecture embodiments is depicted byFIG. 9.

FIG. 9 is a simplified signal flow diagram illustrating a network-basedsolution to signal robustness information to eNBs 930, 940 in a wirelesscommunication system 900, according to some embodiments. The wirelesscommunication system 900 includes a first UE 910 (sometimes referred toherein as “UE1” 910), a second UE 920 (sometimes referred to herein as“UE2” 920), a first eNB 930 (sometimes referred to herein as “eNB1”930), a second eNB 940 (sometimes referred to herein as “eNB 2” 940) afirst EPC/PCRF 952, a second EPC/PCRF 954, and an IMS 956.

In operation, UE1 910 generates and transmits an SDP offer message 902to UE2 920. UE2 920 generates an transmits an SDP answer message 904 toUE1 902. In some embodiments, the EPC/PCRF 952, 954 by default does notknow the MTSI client adaptation behavior, and would therefore set therobustness parameter (e.g., Maximum Packet Loss Rate) based on the leastrobust codec mode among the negotiated codec configurations. MTSI is amultimedia telephony service for the Internet Protocol multimedia corenetwork subsystem. If, however, the EPC/PCRF 952, 954 knows from the SDPthat the MTSI client receiver supports adaptation to the most robustcodec mode (e.g., that the UE 910, 920 will request the sender to changeits encoder to a more robust mode when it detects packet losses), thenthe PCRF could set the robustness parameter based on the most robustcodec mode. This would enable a more optimized SRVCC handoverperformance. Such indication to the EPC/PCRF 952, 954 is enabled via anew SDP parameter called “adapt.” The EPC/PCRF 952, 544 may transmitrobustness information 906, 908 (e.g., Max PLR) to the eNBs 930, 940.

UE-Based Architecture Embodiments

The UE-based embodiments may rely on the fact that the information onthe negotiated codecs and configurations (or codec modes) for thesession is available in the UEs through their knowledge of the SDP thatcontains the negotiated session parameters. Based on such information,the UEs can derive the relevant robustness parameter (e.g., MaximumPacket Loss Rate) and signal this to the eNBs. Such signaling from a UEto an eNB would have to be defined in the RAN, (e.g., via use of RadioResource Control (RRC) signaling) to carry the robustness parameterinformation in TS 36.331 (the exact format of the signaling may bedecided by RAN2). The derivation of the robustness parameter informationbased on the negotiated codec modes can be performed subject to astandardized mapping rule (e.g., with an indication of packet loss ratefor each codec mode and calculation of the Maximum Packet Loss Ratebased on the negotiated codec modes). The UE-based solution is depictedin FIG. 10.

FIG. 10 is a simplified signal flow diagram illustrating a UE-basedsolution to signal robustness information to eNBs 1030, 1040 in awireless communication system 1000, according to some embodiments. Thewireless communication system 1000 includes a first UE 1010 (sometimesreferred to herein as “UE1” 1010), a second UE 1020 (sometimes referredto herein as “UE2” 1020), a first eNB 1030 (sometimes referred to hereinas “eNB1” 1030), a second eNB 1040 (sometimes referred to herein as “eNB2” 1040), a first EPC/PCRF 1052, a second EPC/PCRF 1054, and an IMS1056.

In operation, UE1 1010 generates and transmits an SDP offer message 1002to UE2 1020. UE2 920 generates an transmits an SDP answer message 904 toUE1 902. For the UE-based embodiments, it can be observed that the UEs1010, 1020 (e.g., MTSI client) not only know the negotiated codecs andconfigurations (or codec modes), but also the selected codecconfiguration or mode for the currently transmitted RTP stream (e.g., asdetermined via the outcome of the media adaptation in the UEs 1010,1020). As such, the UEs 1010, 1020 can determine the packet loss ratecorresponding to the selected codec configuration and signal therelevant robustness parameter information 1016, 1018 (e.g., Max PLR) tothe eNBs 1030, 1040. Therefore, an indication at the SDP level via the“adapt” parameter is not necessary for the UE-based signaling solution,and an optimized SRVCC handover performance can be ensured withoutsupporting the “adapt” feature in the SDP and enforcing a particularadaptation behavior on the MTSI client in the UE. Moreover, depending onthe change in the selected codec configuration or mode, the UEs 1010,1020 can dynamically update the eNBs 1030, 1040 on the correspondingrobustness parameter information (e.g., updated value for Max PLR).

Enhancements

In addition to the negotiated codecs and codec modes, the end-to-endquality and robustness of the VoLTE connection also depends on UEcapabilities including, for example, jitter buffer management (JBM) andpacket loss concealment (PLC). In the meantime, the Max PLR parameterderived by the PCRF (e.g., in the network-based architecture above) orthe UE (e.g., in the UE-based architecture above) and signaled to theeNB does not capture the impact of such UE capabilities. As such,further refinements on Max PLR could be considered on a per UE basis,depending on the capabilities of the UE.

The UE may consider its JBM capabilities, its PLC capabilities, itsreal-time quality of experience (QoE) measurements, or combinationsthereof to derive a recommended Max PLR value. In other words the UE mayconsider these factors to determine a recommended maximum end-to-endpacket loss rate that the terminal can tolerate for a given codec/modewhen using its JBM and PLC implementation. The UE may signal thisparameter, or some indication derived from it, to the network (e.g., tothe eNB). The robustness parameter values used in the eNB may then use,or be refined based on, this recommendation. A UE with advanced JBM andPLC capabilities may determine a recommended Max PLR value that ishigher than the Max PLR corresponding to the most robust codecconfiguration. This means that the PLC and JBM capabilities of the UEmay be delivering further robustness on top of that delivered by themost robust codec configuration. If the eNB gets such an indication ofadditional robustness from the UE via the recommended Max PLR signaling,it may further delay the SRVCC handover decision even when the Max PLRvalue (based on the most robust codec configuration) is exceeded. Thisleads to more optimized SRVCC handovers. Furthermore, since there aretypically two radio links in the end-to-end path from the sendingterminal to the receiving terminal, the information is shared with thetwo eNBs in the transport path to determine how to set their SRVCChandover thresholds to achieve appropriate packet_loss_rate targets.

It should be noted that this recommended Max PLR value is an additionalparameter for consideration by the eNB, on top of the Max PLR value theeNB would receive from the PCRF (in case of the network-basedarchitecture) or from the UE (in case of the UE-based architecture). Ifthis information, or any other information derived from it, is to besignaled to the eNB, suitable RAN-level signaling of this informationfrom the UE to the eNB (e.g., at the RRC level as in TS 36.331) shouldbe defined.

FIG. 11 is a simplified illustration of a wireless communication system1100, according to some embodiments. One of the challenges in settingthe handover thresholds is to ensure that the end-to-end error rateacross the transport path from the media sender to the receiver does notexceed the maximum packet loss (Max PLR) that the codec, the PLCimplementation, and the JBM implementation in the receiving UE canhandle. To illustrate, the wireless communication system 1100 includes aUE A 1110, a UE B 1120, an eNB A 1130, and an eNB B 1140. FIG. 11illustrates an end-to-end VoLTE flow 1170 from UE B 1120 to UE A 1110and an end-to-end VoLTE flow 1180 from UE A 1110 to UE B 1120. In theend-to-end VoLTE flow 1170, an eNB A downlink PLR 1176 is the maximumPLR value to be set as the threshold to trigger SRVCC for the DLconnection between eNB A 1130 and UE A 1120. Likewise, eNB_B_UL_PLR 1172is the maximum PLR value to be set as the threshold to trigger SRVCC forthe UL connection between eNB B and UE B. It is assumed that a backhaul1174 between eNB B 1140 and eNB A 1130 introduces negligible error.Under this assumption, the following PLR condition should be maintained:(eNB A downlink PLR 1176)+(eNB B uplink PLR 1172)≤Max PLR codec and(PLC+JBM in UE A 1110)

As such, UE A 1110 can determine the maximum PLR it can tolerate basedon its PLC and JBM implementation and then decide how this should bedistributed between eNB A downlink PLR 1176 and eNB B uplink PLR 1172.In particular, UE A 1110 can decide on the value of eNB A downlink PLR1176 based on the evaluation of the local downlink radio conditionsbetween UE A 1110 and eNB A 1130, and then determine eNB B uplink PLR1172 by subtracting eNB A downlink PLR 1176 from the maximum end-to-endPLR (Max PLR at UE A 1110). While UE A 1110 can signal eNB A downlinkPLR 1176 to its eNB A 1130 locally over the RAN interface (e.g., via RRCsignaling), UE A 1110 may not signal eNB B uplink PLR 1172 to eNB B1140. To signal eNB B uplink PLR 1172 to eNB B 1140, an RTCP signalingapproach described below in the section titled “APPLICATION LAYERSIGNALING OF MAX PLR INFORMATION” may be implemented. Also, UE B 1120cannot signal eNB B uplink PLR 1172 to eNB B 1140 because UE B 1120 doesnot know eNB B uplink PLR 1172. To inform UE B 1120 of eNB B uplink PLR1172 and enable UE B 1120 to signal eNB B uplink PLR 1172 to eNB B 1140,it is proposed herein that the RTCP signaling method proposed in thesection titled “APPLICATION LAYER SIGNALING OF MAX PLR INFORMATION” beused. UE B 1120 can then signal the eNB B uplink PLR 1172 to eNB B 1140locally over its RAN interface. Based on the evaluation of the localuplink radio conditions between UE B 1120 and eNB B 1140, UE B 1120 mayfurther update the value of eNB B uplink PLR 1172 and send thisinformation to UE A 1110 via an RTP header extension method proposed inthe section titled “APPLICATION LAYER SIGNALING OF MAX PLR INFORMATION.”As such, both the media receiver and the media sender have means toexchange UL PLR information in order to dynamically optimize theallocation of DL PLR and UL PLR and lead to the most optimal selectionof the SRVCC handover thresholds on both ends of the link (e.g., theend-to-end VoLTE flow 1170).

In other embodiments, UE A 1110 can determine the maximum PLR it cantolerate based on its PLC and JBM implementation and then UE B 1120 maylearn this maximum PLR value during the SDP negotiations. As such, UE B1120 (as the media sender) may then decide how this should bedistributed between eNB A downlink PLR 1176 and eNB B uplink PLR 1172.In particular, UE B 1120 can decide on the value of eNB B uplink PLR1172 based on the evaluation of the local downlink radio conditionsbetween UE B 1120 and eNB B 1140, and then determine eNB A downlink PLR1176 by subtracting eNB B uplink PLR 1172 from the maximum end-to-endPLR (Max PLR at UE A 1110). It is proposed herein that the RTP headerextension method proposed in the section titled “APPLICATION LAYERSIGNALING OF MAX PLR INFORMATION” be used in order to convey theinformation on eNB A downlink PLR 1176 from UE B 1120 to UE A 1110. UE A1110 can then signal this information to eNB A 1130 locally over its RANinterface.

In some embodiment, the proposed RTP header extension method may be usedto convey the DL and UL PLR allocations for both forward and backwardRTP streams.

Similarly, in the other direction of transmitting media from UE A 1110to UE B 1120 (end-to-end VoLTE flow 1180), the following PLR conditionsshould be maintained (assuming that backhaul 1184 between eNB A 1130 andeNB B 1140 introduces negligible error):(eNB A uplink PLR 1182)+(eNB B downlink PLR 1186)≤max PLR codec and(PLC+JBM in UE B 1120)Here, eNB B downlink PLR 1186 is the maximum PLR value to be set as thethreshold to trigger SRVCC for the DL connection between eNB B 1140 andUE B 1120. Likewise, eNB A uplink PLR 1182 is the maximum PLR value tobe set as the threshold to trigger SRVCC for the UL connection betweeneNB A 1130 and UE A 1110.

As such, UE B 1120 can determine the maximum PLR it can tolerate basedon its PLC and JBM implementation and then decide how this should bedistributed between eNB A uplink PLR 1182 and eNB B downlink PLR 1186.In particular, UE B 1120 can decide on the value of eNB B downlink PLR1186 based on the evaluation of the local downlink radio conditionsbetween UE B 1120 and eNB B 1140, and then determine eNB A uplink PLR1182 by subtracting eNB B downlink PLR 1186 from the maximum end-to-endPLR (Max PLR at UE B 1120). While UE B 1120 can signal eNB B downlinkPLR 1186 to its eNB B 1140 locally over the RAN interface (e.g., via RRCsignaling), UE B 1120 cannot signal eNB A uplink PLR 1182 to eNB A 1130.UE A 1110 cannot signal eNB A uplink PLR 1182 to eNB A 1130 because UE A1110 does not know the eNB A uplink PLR 1182. To inform UE A 1110 of theeNB A uplink PLR 1182, it is proposed herein that the RTCP signalingmethod of the section titled “APPLICATION LAYER SIGNALING OF MAX PLRINFORMATION” be used. UE A 1110 can then signal the eNB A uplink PLR1182 to eNB A 1130 locally over its RAN interface. Based on theevaluation of the local uplink radio conditions between UE A 1110 andeNB A 1130, UE A 1110 may further update the value of eNB A uplink PLR1182 and send this information to UE B 1130 via the use of the RTPheader extension method proposed in the section titled “APPLICATIONLAYER SIGNALING OF MAX PLR INFORMATION.”

In some embodiments, the transmitting UE (UE B 1120 for flow 1170 and UEA 1110 for flow 1180) can estimate also the UE PLR and send thisinformation to the receiving UE (UE A 1110 for flow 1170 and UE B 1120for flow 1180) via the RTP header extension method. In the end, a DL UEcan have the following information: (i) Missing RTP packet, (ii)Measured PLR from MAC/PHY in DL, and (iii) Estimated PLR from the ULsender UE. Based on this information, the UE may determine if somepacket loss has happened in the network itself. This information maythen be used for network diagnosis. The UE may trigger a report to thenetwork or media gateway. In addition to PLR, the UE may report adistribution indication. For instance, to a same average PLR, the packetloss can be evenly distributed, or there may be a short interruption andthen normal transmission.

Application Layer Signaling of Max PLR Information

While RAN-layer delay budget reporting may allow UEs to locally adjustair interface delay, such a mechanism may not provide coordinationbetween the UEs to manage delay and jitter on an end-to-end basis. Toenable the dynamic allocation of UL PLR and DL PLR as discussed above,the following RTP/RTCP signaling (e.g., to signal delay budgetinformation and/or Max PLR information across UEs) and RTP headerextension frameworks can be considered in order to exchange UL Max PLRinformation as described above (or other kinds of information ofequivalent context):

-   -   A new RTCP feedback (FB) message type to carry Max PLR or uplink        packet loss ratio (UL PLR) information during the RTP streaming        of media may be implemented (signaled from a media receiver to a        media sender);    -   A new SDP parameter on the RTCP-based ability to signal Max PLR        or UL PLR information during the IMS/session initiation protocol        (SIP) based capability negotiations;    -   A new RTP header extension type to signal for UL PLR information        during the RTP streaming of media (signaled from a media sender        to a media receiver);    -   A new SDP parameter on the RTP-based ability to signal UL PLR        information during the IMS/SIP-based capability negotiations;    -   A new RTP header extension type to signal for UL PLR information        during the RTP streaming of media for the reverse stream        (signaled from a media receiver to a media receiver); and    -   A new SDP parameter on the RTP-based ability to signal UL PLR        information during the IMS/SIP-based capability negotiations for        the reverse stream.

The signaling of Max or UL PLR information may use RTCP feedbackmessages as specified in IETF 4585. As such, the RTCP feedback messageis sent from the MTSI receiver to the MTSI sender to convey to thesender about the tolerable Max or UL PLR information. The recipient ofthe RTCP feedback message may then convey this information to its eNBover the RAN interface (e.g., by using RRC signaling).

The RTCP feedback message is identified by PT=PSFB (206). FMT shall beset to the value “Y” for UL PLR information. The RTCP feedback methodmay involve signaling of Max or UL PLR information in both of theimmediate feedback and early RTCP modes.

In some embodiments the FCI format can be as follows: the FCI cancontain exactly one instance of the Max or UL PLR information, whichincludes the Max or UL PLR value “ULPLR,” which may be specified inmilliseconds (e.g., 16 bits). It should be noted that this FCI format isfor illustration purposes, and other formats can also be defined toconvey Max or UL PLR information. The FCI for the proposed RTCP feedbackmessage can follow the format shown by FIG. 12.

FIG. 12 is a simplified illustration of an example FCI format of an RTCPfeedback message 1200, according to some embodiments. The RTCP feedbackmessage 1200 includes the parameter ULPLR 1260 and zero padding 1270.The high byte should be followed by the low byte, where the low byteholds the least significant bits.

FIG. 13 is a simplified illustration of an example FCI format of an RTCPfeedback message 1300, according to some embodiments. In some suchembodiments, the ratio between UL PLR and DL PLR values may be signaledby the RTCP feedback message 1300 (e.g., signaled with a 16-bitparameter). Accordingly, the RTCP feedback message may include aparameter UL_DL_PLR_Ratio 1360 indicating this ratio of UL PLR and DLPLR values, and may, for example, be specified in 16 bits. The RTCPfeedback message 1300 may also include zero padding 1370.

FIG. 14 is a simplified illustration of a format of an example RTPheader extension message 1400, according to some embodiments. A 3GPPMTSI client (based on TS 26.114) supporting the RTCP feedback messagesdiscussed above can offer such capability in the SDP for all mediastreams containing video/audio. The offer can be made by including thea=rtcp-fb attribute in conjunction with the following parameter:3gpp-max/ul-plr. A wildcard payload type (“*”) may be used to indicatethat the RTCP feedback attribute applies to all payload types. Anexample usage of this attribute may be as follows:

-   -   a=rtcp-fb:*3gpp-max/ul-plr

The ABNF for rtcp-fb-val corresponding to the feedback type“3gpp-max/ul-plr” may be as follows:

-   -   rtcp-fb-val=/“3gpp-max/ul-plr”

In some settings, the UL PLR information may also be signaled by theMTSI sender to the MTSI receiver as part of the transmitted RTP streamusing RTP header extensions, as discussed above. An example format isshown by FIG. 14, where UL PLR value ULPLR 1460 is specified in 16 bits.The example RTP header extension message 1400 also includes an ID 1462,a len=7 1464, and zero padding 1470.

FIG. 15 is a simplified illustration of a format of an example RTPheader extension message 1500, according to some embodiments. In someembodiments, the ratio between UL PLR and DL PLR values may be signaledinstead in the RTP header extension message 1500, potentially againspecified via 16 bits. The following format may be used: Ratio of UL PLRand DL PLR values UL_DL_PLR_Ratio 1560 (e.g., specified in 16 bits). Theexample RTP header extension message 1500 also includes an ID 1562,len=7 1564, and zero padding 1570.

FIG. 16 is a simplified illustration of a format of an example RTPheader extension message 1600, according to some embodiments. In someembodiments, the RTP header extension method may be used to convey theDL and UL PLR allocations for both forward and backward RTP streams.Such embodiments may include a format of a ratio of UL PLR and DL PLRvalues UL_DL_PLR_Ratio1 1660A for forward link (e.g., specified in 12bits); and/or a ratio of UL PLR and DL PLR values UL_DL_PLR_Ratio2 1660Bfor reverse link (e.g., specified in 12 bits). The RTP header extensionmessage 1600 also includes an ID 1662, and a len=7 1664.

A 3GPP MTSI client supporting this RTP header extension message canoffer such capability in the SDP for all media streams containingvideo/audio. This capability can be offered by including the a=extmapattribute indicating a dedicated URN under the relevant media linescope. The URN corresponding to the capability to signal UL PLRinformation is: urn:3gpp:ul-plr. An example usage of this URN in the SDPfollows:

-   -   a=extmap:7 urn:3gpp:ul:plr        The number 7 in the example may be replaced with any number in        the range 1-14.

In some embodiments the UL PLR information may also be signaled by theMTSI receiver to the MTSI receiver as part of the reverse RTP streamusing RTP header extensions, as described above. The above RTP headerextension format may also be used in this context. FIG. 17 shows anexample procedure (signaling flows) of the above dynamic DL PLR and ULPLR allocation framework based on the use of RTCP feedback signaling.

FIG. 17 is a simplified signal flow diagram illustrating end-to-endapplication layer signaling of Max PLR in a wireless communicationsystem 1700, according to some embodiments. FIG. 17 is an example usageof dynamic DL PLR and UL PLR allocation framework based on the use ofRTCP feedback signaling. The wireless communication system 1700 includesa UE A 1710, a UE B 1720, an eNB A 1730, an eNB B 1740, a first EPC1752, a second EPC 1754, and an IMS 1756. For purposes of FIG. 17, eNB A1730 is servicing UE A 1710 and eNB B 1740 is servicing UE B 1720.

In operation, UE A 1710 and UE B 1720 exchange SDP negotiations 1788.These SDP negotiations 1788 include information on (i) max_e2e_PLR on UEA 1710 and UE B 1720, (ii) RTCP-based ability to signal UL PLRinformation as discussed above, and (iii) RTP header extension-basedcapability to exchange UL PLR information as discussed above. Followingthe SDP negotiations 1788, it is possible that DL PLR and UL PLR valuesmay be statically configured and the respective SRVCC thresholds may bedetermined. For instance, from the perspective of UE B 1720, this meanseNB B downlink PLR and eNB A uplink PLR are also statically set.

UE A 1710 sends an RTP media flow 1792 to UE B 1720. In some instances,UE B 1720 detects 1794 DL good radio conditions locally (e.g., UE B 1720measures low BLER over the local radio link). As a result, UE B 1720concludes that the local radio conditions will support the most robustcodec mode with negligibly small PLR. The chances of SRVCC handover inthis instance are quite small. On the contrary, in some instances UE A1710 detects 1796 UL poor radio conditions locally (e.g., UE A 1710measures high BLER over the local radio link). As a result, UE A 1710concludes that the local radio conditions may hardly support the mostrobust codec mode, and that there is a good chance that SRVCC handoverwill need to be triggered.

UE B 1720 sends to UE A 1710 an RTCP feedback message 1797 including ULPLR information, where the eNB A uplink PLR value is set to a valuerelatively close to max_e2e_PLR for UE B 1720. UE A 1710 signals 1798the new UL PLR value to eNB A 1730. Then eNB A 1730 updates its SRVCChandover threshold based on the new UL PLR value, which is higher thanthe statically set UL PLR value. As a result, SRVCC handover over the ULconnection from UE A 1710 to eNB A 1730 is improved 1799 (e.g., delayedfurther due to the dynamically signaled UL PLR information from UE B1720).

In some embodiments, the electronic device(s), network(s), system(s),chip(s) or component(s), or portions or implementations thereof, of anyfigure herein may be configured to perform one or more processes,techniques, or methods as described herein, or portions thereof.

Examples B

The following is another non-exhaustive list of example embodiments thatfall within the scope of the disclosure. In order to avoid complexity inproviding the disclosure, not all of the examples listed below areseparately and explicitly disclosed as having been contemplated hereinas combinable with all of the others of the examples listed below andother embodiments disclosed hereinabove. Unless one of ordinary skill inthe art would understand that these examples listed below, the exampleslisted in Examples A above, and the above disclosed embodiments, are notcombinable, it is contemplated within the scope of the disclosure thatsuch examples and embodiments are combinable.

Example 1 may include a local user equipment (UE) operable to performmultimedia telephony with a remote UE, the local UE having one or moreprocessors to: communicate, from the local UE to the remote UE, themaximum packet loss ratio (Max PLR) information via a real-timetransport control protocol (RTCP) feedback message; and based on thesignaled Max PLR information, the remote UE requests from its localevolved NodeB eNB to adjust the single radio voice call continuity(SRVCC) handover threshold of its uplink connection based on the Max PLRvalue.

Example 2 may include the local UE of Example 1 or some other exampleherein, wherein Max PLR information pertains to the maximum packet lossratio for the uplink radio connection from the remote UE to its localeNB.

Example 3 may include the local UE of Example 1 or some other exampleherein, wherein the one or more processors are further to receive asession description protocol (SDP) offer message from the remote UE thatincludes a real-time transport control protocol (RTCP) feedbackattribute that is associated with a Third Generation Partnership Project(3GPP) 3gpp-max-plr parameter, thereby indicating that the remote UEsupports the reception of Max PLR information signaled via RTCP feedbackmessages.

Example 4 may include the local UE of Example 1 or some other exampleherein, wherein the one or more processors are further to send a sessiondescription protocol (SDP) answer message to the remote UE that includesa real-time transport control protocol (RTCP) feedback attribute that isassociated with a Third Generation Partnership Project (3GPP)3gpp-max-plr parameter, thereby acknowledging that the local UE supportsthe transmission of Max PLR information signaled via RTCP feedbackmessages.

Example 5 may include the local UE of Example 1 or some other exampleherein, wherein the RTCP feedback message communicated from the local UEto the remote UE includes a descriptor that contains Max PLRinformation.

Example 6 may include the local UE of Example 1 or some other exampleherein, wherein the Max PLR information is determined based on thedifference between local UE's assessment of how much end-to-end Max PLRthe local UE can tolerate during reception based on its jitter buffermanagement and packet loss concealment capabilities and packet lossratio value estimate of the local downlink radio conditions between thelocal UE and its eNB.

Example 7 may include a local user equipment (UE) operable to performmultimedia telephony with a remote UE, the local UE having one or moreprocessors configured to: communicate, from the local UE to the remoteUE, an indication of the uplink (UL) maximum packet loss ratio (MaxPLR)information for the media RTP stream delivered from the remote UE to thelocal UE via a real-time transport control protocol (RTCP) feedbackmessage; based on the signaled uplink MaxPLR information, the remote UErequests from its local eNB to adjust the SRVCC handover threshold ofits uplink (UL) connection based on the uplink MaxPLR value.

Example 8 may include the local UE of Example 7 or some other exampleherein, wherein the indication of the uplink MaxPLR information pertainsto the maximum tolerable packet loss ratio value for the uplink (UL)radio connection from the remote UE to its local eNB above which SRVCChandover must be activated.

Example 9 may include the local UE of Example 7 or some other exampleherein, wherein the indication of the uplink MaxPLR information pertainsto the ratio of (the maximum tolerable packet loss ratio value for theuplink (UL) radio connection from the remote UE to its local eNB abovewhich SRVCC handover must be activated) and (the maximum tolerablepacket loss ratio value for the downlink (DL) radio connection from thelocal UE and its local eNB above which SRVCC handover must beactivated).

Example 10 may include the local UE of Example 7 or some other exampleherein, wherein the one or more processors are further configured toreceive a session description protocol (SDP) offer message from theremote UE that includes an RTCP feedback attribute that is associatedwith a Third Generation Partnership Project (3GPP) 3gpp-ul-plrparameter, thereby indicating that the remote UE supports the receptionof UL MaxPLR information signaled via RTCP feedback messages.

Example 11 may include the local UE of Example 7 or some other exampleherein, wherein the one or more processors are further configured tosend a session description protocol (SDP) answer message to the remoteUE that includes an RTCP feedback attribute that is associated with aThird Generation Partnership Project (3GPP) 3gpp-ul-plr parameter,thereby acknowledging that the local UE supports the transmission of ULMaxPLR information signaled via RTCP feedback messages.

Example 12 may include the local UE of Example 7 or some other exampleherein, wherein the RTCP feedback message communicated from the local UEto the remote UE includes a descriptor that contains UL MaxPLRinformation.

Example 13 may include the local UE of Example 7 or some other exampleherein, wherein the UL MaxPLR information is determined based on thedifference between (local UE's assessment of how much end-to-end MaxPLRthe local UE can tolerate during media reception from the remote UEbased on the negotiated codec modes and its jitter buffer management andpacket loss concealment capabilities) and (packet loss ratio to serve asthe SRVCC handover threshold value for the local downlink (DL)connection to the local UE, considering local UE's assessment of theradio conditions between the local UE and its eNB).

Example 14 may include the local UE of Example 7 or some other exampleherein, wherein the remote UE communicates to the local UE, anindication of the uplink maximum packet loss ratio (UL MaxPLR)information for the media RTP stream delivered from the remote UE to thelocal UE via a real-time transport protocol (RTP) header extensionmessage and based on the signaled UL MaxPLR information, the local UErequests from its local eNB to adjust the SRVCC handover threshold ofits downlink (DL) connection based on the received UL MaxPLR value.

Example 15 may include the local UE of Example 14 or some other exampleherein, wherein the indication of the uplink MaxPLR information pertainsto the maximum tolerable packet loss ratio value for the uplink (UL)radio connection from the remote UE to its local eNB above which SRVCChandover must be activated.

Example 16 may include the local UE of Example 14 or some other exampleherein, wherein the indication of the uplink MaxPLR information pertainsto the ratio of (the maximum tolerable packet loss ratio value for theuplink (UL) radio connection from the remote UE to its local eNB abovewhich SRVCC handover must be activated) and (the maximum tolerablepacket loss ratio value for the downlink (DL) radio connection from thelocal UE and its local eNB above which SRVCC handover must beactivated).

Example 17 may include the local UE of Example 7 or some other exampleherein, wherein the UL MaxPLR information in the RTP header extensionmessage is determined by the remote UE to be the packet loss ratio toserve as the SRVCC handover threshold value for the uplink (DL)connection from the remote UE to its eNB, considering remote UE'sassessment of the radio conditions between the remote UE and its eNB.

Example 18 may include the local UE of Example 14 or some other exampleherein, wherein the one or more processors are further configured toreceive a session description protocol (SDP) offer message from theremote UE that includes an extension map attribute that is associatedwith a Third Generation Partnership Project (3GPP) ul-plr parameter,thereby indicating that the remote UE supports transmission of uplinkMaxPLR information signaled via RTP header extension messages.

Example 19 may include the local UE of Example 14 or some other exampleherein, wherein the one or more processors are further configured tosend a session description protocol (SDP) answer message to the remoteUE that includes an extension map attribute that is associated with aThird Generation Partnership Project (3GPP) ul-plr parameter, therebyacknowledging that the local UE supports reception of uplink MaxPLRinformation signaled via RTP header extension messages.

Example 20 may include the local UE of Example 14 or some other exampleherein, wherein the RTP header extension message communicated from theremote UE to the local UE includes a descriptor that contains UL MaxPLRinformation

Example 21 may include the local UE of Example 14 or some other exampleherein, wherein the SRVCC handover threshold for the downlink (DL)connection between the local UE and its eNB is adjusted based on thedifference between (local UE's assessment of how much end-to-end MaxPLRthe local UE can tolerate during media reception from the remote UEbased on the negotiated codec modes and its jitter buffer management andpacket loss concealment capabilities) and (UL MaxPLR value in thereceived RTP header extension message from the remote UE).

Example 22 may include a local user equipment (UE) operable to performmultimedia telephony with a remote UE, the local UE having one or moreprocessors configured to: communicate, from the local UE to the remoteUE, an indication of the downlink (DL) maximum packet loss ratio(MaxPLR) information for the media RTP stream delivered from the localUE to the remote UE via a RTP header extension message, and based on thesignaled downlink MaxPLR information, the remote UE requests from itslocal eNB to adjust the SRVCC handover threshold of its downlink (DL)and/or uplink (UL) connection based on the downlink MaxPLR value.

Example 23 may include the local UE of Example 22 or some other exampleherein, wherein the local UE obtains the maximum end-to-end PLR of theremote UE during the capability negotiation using the sessiondescription protocol (SDP)

Example 24 may include the local UE of Example 22 or some other exampleherein, wherein the indication of the downlink MaxPLR informationpertains to the maximum tolerable packet loss ratio value for thedownlink (DL) radio connection between the remote UE to its local eNBabove which SRVCC handover must be activated

Example 25 may include the local UE of Example 22 or some other exampleherein, wherein the indication of the downlink MaxPLR informationpertains to the ratio of (the maximum tolerable packet loss ratio valuefor the uplink (UL) radio connection from the remote UE to its local eNBabove which SRVCC handover must be activated) and (the maximum tolerablepacket loss ratio value for the downlink (DL) radio connection from thelocal UE and its local eNB above which SRVCC handover must be activated)

Example 26 may include the local UE of Example 22 or some other exampleherein, wherein the one or more processors are further configured toreceive a session description protocol (SDP) offer message from theremote UE that includes an extension map attribute that is associatedwith a Third Generation Partnership Project (3GPP) dl-plr parameter,thereby indicating that the remote UE supports reception of downlinkMaxPLR information signaled via RTP header extension messages.

Example 27 may include the local UE of Example 22 or some other exampleherein, wherein the one or more processors are further configured tosend a session description protocol (SDP) answer message to the remoteUE that includes an extension map attribute that is associated with aThird Generation Partnership Project (3GPP) dl-plr parameter, therebyacknowledging that the local UE supports transmission of downlink MaxPLRinformation signaled via RTP header extension messages.

Example 28 may include the local UE of Example 22 or some other exampleherein, wherein the RTP header extension message communicated from thelocal UE to the remote UE includes a descriptor that contains DL MaxPLRinformation

Example 29 may include the local UE of Example 22 or some other exampleherein, wherein the RTP header extension message communicated from thelocal UE to the remote UE includes a descriptor that contains ratiobetween UL MaxPLR and DL MaxPLR information

Example 30 may include the local UE of Example 22 or some other exampleherein, wherein the DL MaxPLR information is determined based on thedifference between (remote UE's assessment of how much end-to-end MaxPLRthe remote UE can tolerate during media reception from the local UEbased on the negotiated codec modes and its jitter buffer management andpacket loss concealment capabilities, with this parameter signalled fromremote UE to local UE) and (packet loss ratio to serve as the SRVCChandover threshold value for the local uplink (UL) connection of thelocal UE, considering local UE's assessment of the radio conditionsbetween the local UE and its eNB).

Example 31 may include an apparatus capable of performing multimediatelephony with a remote device, the apparatus comprising: communicationmeans for transmitting, via a real-time transport control protocol(RTCP) feedback message, an uplink (UL) maximum packet loss ratio(MaxPLR) indication that is to include information for a media RTPstream delivered from the remote device to the apparatus, wherein the ULMaxPLR information is for requesting adjustment of a Single Radio VoiceCall Continuity (SRVCC) handover (HO) threshold of a UL connection ofthe remote device based on a UL MaxPLR value in the UL MaxPLRindication.

Example 32 may include the apparatus of Example 31 or some other exampleherein, wherein the UL MaxPLR indication is to indicate a maximumtolerable packet loss ratio value for the UL radio connection from theremote device to a remote evolved NodeB (eNB) above which an SRVCC HO isto be activated.

Example 33 may include the apparatus of Example 31 or some other exampleherein, wherein the UL MaxPLR indication is to indicate:

a ratio of a maximum tolerable packet loss ratio value for the UL radioconnection from the remote device to the remote eNB above which an SRVCCHO is to be activated, and a maximum tolerable packet loss ratio valuefor a downlink (DL) radio connection from the apparatus to a local eNBabove which an SRVCC HO is to be activated.

Example 34 may include the apparatus of Example 31 or some other exampleherein, wherein the communication means is for receiving a sessiondescription protocol (SDP) offer message from the remote device, whereinthe SDP offer message is to include an RTCP feedback attribute that isassociated with a Third Generation Partnership Project (3GPP) parameter(3gpp-ul-plr), wherein the 3gpp-ul-plr is to indicate that the remotedevice supports reception of UL MaxPLR information signaled via RTCPfeedback messages.

Example 35 may include the apparatus of Example 36 or some other exampleherein, wherein the communication means is for transmitting an SDPanswer message to the remote device, wherein the SDP answer is toinclude the 3gpp-ul-plr, wherein the 3gpp-ul-plr is to indicateacknowledgment that the apparatus supports the transmission of UL MaxPLRinformation signaled via RTCP feedback messages.

Example 36 may include the apparatus of Example 35 or some other exampleherein, wherein the RTCP feedback message is to include a descriptorthat comprises the UL MaxPLR information.

Example 37 may include the apparatus of Example 31 or some other exampleherein, further comprising: means for determining the UL MaxPLRinformation based on a difference between an (1) assessment of how muchend-to-end MaxPLR the apparatus is capable of tolerating during mediareception from the remote device based on an negotiated codec modes anda jitter buffer management and packet loss concealment capabilities, and(2) a packet loss ratio to serve as an SRVCC HO threshold value for a DLconnection to the apparatus, wherein (2) is in consideration of theassessment of radio conditions between the apparatus and the local eNB.

Example 38 may include the apparatus of Example 31 or some other exampleherein, wherein the communication means is for: receiving, from theremote device via an RTP header extension message, another UL MaxPLRindication to include information for the media RTP stream deliveredfrom the remote device to the apparatus, wherein the other UL MaxPLRindication is based on the signaled UL MaxPLR indication, andtransmitting a request to the local eNB to adjust an SRVCC HO thresholdof a DL radio connection based on a UL MaxPLR value in the other ULMaxPLR indication.

Example 39 may include the apparatus of Example 38 or some other exampleherein, wherein the other UL MaxPLR indication is to indicate a maximumtolerable packet loss ratio value for a UL radio connection from theremote device to a remote eNB above which an SRVCC HO is to beactivated.

Example 40 may include the apparatus of Example 38 or some other exampleherein, wherein the UL MaxPLR indication is to indicate a ratio of amaximum tolerable packet loss ratio value for the UL radio connectionfrom the remote device to the remote eNB above which an SRVCC HO is tobe activated and a maximum tolerable packet loss ratio value for the DLradio connection from the apparatus and the local eNB above which SRVCChandover is to be activated.

Example 41 may include the apparatus of Example 38 or some other exampleherein, wherein the other UL MaxPLR indication in the RTP headerextension message is determined by the remote device to be a PLR toserve as the SRVCC HO threshold value for the UL connection from theremote device to the remote eNB based on an assessment of radioconditions between the remote device to the remote eNB.

Example 42 may include the apparatus of Example 38 or some other exampleherein, wherein the communication means are for receiving an SDP offermessage from the remote device, wherein the SDP offer message is toinclude an extension map attribute that is associated with a 3GPP ul-plrparameter, wherein the ul-plr parameter is to indicate that the remotedevice supports transmission of uplink MaxPLR information signaled viaRTP header extension messages.

Example 43 may include the apparatus of Example 42 or some other exampleherein, wherein the communication means are for transmitting an SDPanswer message to the remote device, wherein the SDP answer message isto include an extension map attribute that is associated with the 3GPPul-plr parameter, wherein the ul-plr parameter is to acknowledge thatthe apparatus supports reception of uplink MaxPLR information signaledvia RTP header extension messages.

Example 44 may include the apparatus of Example 38 or some other exampleherein, wherein the RTP header extension message is to include adescriptor that includes the other UL MaxPLR information.

Example 45 may include the apparatus of Example 38 or some other exampleherein, wherein the SRVCC HO threshold for the DL connection between (1)the apparatus and the local eNB is adjusted based on a differencebetween an assessment of how much end-to-end MaxPLR the apparatus cantolerate during media reception from the remote device based onnegotiated codec modes and jitter buffer management and packet lossconcealment capabilities, and (2) UL MaxPLR value in the received RTPheader extension message from the remote UE.

Example 46 may include the apparatus of Example 31-45 or some otherexample herein, wherein: the communication means is for transmitting anRTP header extension message, wherein the RTP header extension messageis to include a downlink (DL) maximum packet loss ratio (MaxPLR)indication for the media RTP stream to be delivered by the communicationmeans to the remote device, and wherein the signaled downlink MaxPLRindication is for the remote device to request from a remote eNB toadjust the SRVCC handover threshold of a remote device DL and/or ULconnection based on the downlink MaxPLR value.

Example 47 may include the apparatus of Example 46 or some other exampleherein, wherein the communication means is for receiving a maximumend-to-end PLR of the remote device during a capability negotiationusing session description protocol (SDP).

Example 48 may include the apparatus of Example 46 or some other exampleherein, wherein the DL MaxPLR indication pertains to a maximum tolerablepacket loss ratio value for the DL radio connection between the remoteUE to its local eNB above which SRVCC handover must be activated.

Example 49 may include the apparatus of Example 46 or some other exampleherein, wherein the DL MaxPLR indication pertains to a ratio of amaximum tolerable packet loss ratio value for the UL radio connectionfrom the remote device to the remote eNB above which an SRVCC handoveris to be activated and a maximum tolerable packet loss ratio value forthe DL radio connection from the apparatus and the local eNB above whichan SRVCC handover is to be activated.

Example 50 may include the apparatus of Example 46 or some other exampleherein, wherein the communication means is for receiving an SDP offermessage from the remote device, the SDP offer message to include anextension map attribute that is associated with a 3GPP dl-plr parameter,the dl-plr parameter indicating that the remote device supportsreception of DL MaxPLR information signaled via RTP header extensionmessages.

Example 51 may include the apparatus of Example 46 or some other exampleherein, wherein the communication means is for transmitting an SDPanswer message to the remote device, the SDP answer message to includean extension map attribute that is associated with a 3GPP dl-plrparameter, the dl-plr parameter to acknowledge that the apparatussupports transmission of DL MaxPLR information signaled via RTP headerextension messages.

Example 52 may include the apparatus of Example 46 or some other exampleherein, wherein the RTP header extension message is to include adescriptor that includes DL MaxPLR information.

Example 53 may include the apparatus of Example 46 or some other exampleherein, wherein the RTP header extension message is to include adescriptor that includes a ratio between UL MaxPLR and DL MaxPLRinformation.

Example 54 may include the apparatus of Example 46 or some other exampleherein, wherein the DL MaxPLR information is determined based on thedifference between an end-to-end MaxPLR that the remote device cantolerate during media reception from the apparatus based on negotiatedcodec modes and a jitter buffer management and packet loss concealmentcapabilities, and a packet loss ratio to serve as the SRVCC handoverthreshold value for a local UL connection of the apparatus, which isbased on an assessment of radio conditions between the apparatus and thelocal eNB, wherein the communication means is for receiving thedifference from the remote device.

Example 55 may include the apparatus of Examples 31-45 or some otherexample herein, wherein the apparatus is implemented in or by a userequipment (UE) and the device is another UE.

Example 56

An apparatus of a user equipment (UE), comprising: circuitry to enablethe UE to perform multimedia telephony with a remote UE, the multimediatelephony including a media real-time transport protocol (RTP) streamdelivered from the remote UE to the local UE; and one or more processorsto generate a real-time transport control protocol (RTCP) feedbackmessage to be transmitted to the remote UE, the RTCP feedback messageincluding an indication of an uplink (UL) maximum packet loss ratio(MaxPLR) for the media RTP stream, the indication of the UL MaxPLR toenable the remote UE to request that a cellular base station servicingthe remote UE adjust, based on the indicated UL MaxPLR value, a singleradio voice call continuity (SRVCC) handover threshold of a remote ULbetween the remote UE and the cellular base station servicing the remoteUE.

Example 57

The apparatus of Example 56, wherein the UL MaxPLR value comprises amaximum tolerable packet loss ratio (PLR) value for the remote UL.

Example 58

The apparatus according to any one of Examples 56 and 57, wherein the ULMaxPLR value comprises a ratio of a maximum tolerable PLR value for theremote UL to a maximum tolerable PLR value for a local downlink (DL)between a cellular base station servicing the UE and the UE.

Example 59

The apparatus according to any one of Examples 56-58, wherein the one ormore processors are further configured to decode a session descriptionprotocol (SDP) offer message received from the remote UE, the SDP offermessage configured to indicate that the remote UE supports reception ofUL MaxPLR information signaled via RTCP feedback messages.

Example 60

The apparatus according to any one of Examples 56-59, wherein the one ormore processors are further configured to generate a session descriptionprotocol (SDP) answer message to be transmitted to the remote UE, theSDP answer message configured to indicate that the UE supportstransmission of UL MaxPLR information signaled via RTCP feedbackmessages.

Example 61

The apparatus according to any one of Examples 56-60, wherein the one ormore processors are further configured to: decode an RTP headerextension message recieved from the remote UE, the RTP header extensionmessage configured to indicate UL MaxPLR information for the media RTPstream; and generate a request to be transmitted to a cellular basestation servicing the UE, the request configured to request that thecellular base station servicing the UE adjust an SRVCC handoverthreshold of its downlink (DL) connection with the UE based on thereceived UL MaxPLR information.

Example 62

An apparatus of a user equipment (UE), comprising: circuitry to enablethe UE to perform multimedia telephony with a remote UE, the multimediatelephony including a media real-time transport protocol (RTP) streamdelivered from the UE to the remote UE; and one or more processors togenerate an RTP header extension message to be transmitted to the remoteUE, the RTP header extension message including an indication of adownlink (DL) maximum packet loss ratio (MaxPLR) for the media RTPstream, the indication of the DL MaxPLR to enable the remote UE torequest that a cellular base station servicing the remote UE adjust,based on the DL MaxPLR value, a single radio voice call continuity(SRVCC) handover threshold of a remote DL between a cellular basestation servicing the remote UE and the remote UE.

Example 63

The apparatus of Example 62, wherein the one or more processors arefurther configured to decode a message received from the remote UEduring a capability negotiation using a session description protocol(SDP), the message indicating a maximum end-to-end packet loss ratio(PLR) of the remote UE.

Example 64

The apparatus according to any one of Examples 62 and 63, wherein the DLMaxPLR information is determined based on a difference between: anassessment by the remote UE of how much end-to-end MaxPLR the remote UEcan tolerate during media reception from the UE based on negotiatedcodec modes, jitter buffer management, and packet loss concealmentcapabilities of the remote UE, and a packet loss ratio to serve as anSRVCC handover threshold value for a local uplink (UL) between the UEand a cellular base station servicing the UE, considering radioconditions between the UE and the cellular base station servicing theUE.

Example 65

The apparatus according to any one of Examples 62-64, wherein the one ormore processors are configured to decode a session description protocol(SDP) offer message received from the remote UE, the SDP offer messageconfigured to indicate that the remote UE supports reception of DLMaxPLR information signaled via RTP header extension messages.

Example 66

The apparatus according to any one of Examples 62-65, wherein the one ormore processors are further configured to generate a session descriptionprotocol (SDP) answer message to be transmitted to the remote UE, theSDP answer message configured to indicate that the UE supportstransmission of DL MaxPLR information signaled via RTP header extensionmessages.

Example 67

The apparatus according to any one of Examples 62-66, wherein the RTPheader extension message includes a ratio between an uplink (UL) MaxPLRand the DL MaxPLR.

Example 68 may include an apparatus comprising means to perform one ormore elements of a method described in or related to any of Examples1-67, or any other method or process described herein.

Example 69 may include one or more non-transitory computer-readablemedia comprising instructions to cause an electronic device, uponexecution of the instructions by one or more processors of theelectronic device, to perform one or more elements of a method describedin or related to any of Examples 1-67, or any other method or processdescribed herein.

Example 70 may include an apparatus comprising logic, modules, orcircuitry to perform one or more elements of a method described in orrelated to any of Examples 1-67, or any other method or processdescribed herein.

Example 71 may include a method, technique, or process as described inor related to any of Examples 1-67, or portions or parts thereof.

Example 72 may include an apparatus comprising: one or more processorsand one or more computer readable media comprising instructions that,when executed by the one or more processors, cause the one or moreprocessors to perform the method, techniques, or process as described inor related to any of Examples 1-67, or portions thereof.

Example 73 may include a signal as described in or related to any ofExamples 1-67, or portions or parts thereof.

Example 74 may include a signal in a wireless network as shown anddescribed herein.

Example 75 may include a method of communicating in a wireless networkas shown and described herein.

Example 76 may include a system for providing wireless communication asshown and described herein.

Example 77 may include a device for providing wireless communication asshown and described herein.

Cellular Communication System Implementation

FIG. 18 illustrates an architecture of a system 1800 of a network inaccordance with some embodiments. The system 1800 is shown to include auser equipment (UE) 1801 and a UE 1802. The UEs 1801 and 1802 areillustrated as smartphones (e.g., handheld touchscreen mobile computingdevices connectable to one or more cellular networks), but may alsocomprise any mobile or non-mobile computing device, such as PersonalData Assistants (PDAs), pagers, laptop computers, desktop computers,wireless handsets, or any computing device including a wirelesscommunications interface.

In some embodiments, any of the UEs 1801 and 1802 can comprise anInternet of Things (IoT) UE, which can comprise a network access layerdesigned for low-power IoT applications utilizing short-lived UEconnections. An IoT UE can utilize technologies such asmachine-to-machine (M2M) or machine-type communications (MTC) forexchanging data with an MTC server or device via a public land mobilenetwork (PLMN), Proximity-Based Service (ProSe) or device-to-device(D2D) communication, sensor networks, or IoT networks. The M2M or MTCexchange of data may be a machine-initiated exchange of data. An IoTnetwork describes interconnecting IoT UEs, which may include uniquelyidentifiable embedded computing devices (within the Internetinfrastructure), with short-lived connections. The IoT UEs may executebackground applications (e.g., keep-alive messages, status updates,etc.) to facilitate the connections of the IoT network.

The UEs 1801 and 1802 may be configured to connect, e.g.,communicatively couple, with a radio access network (RAN) 1810. The RAN1810 may be, for example, an Evolved Universal Mobile TelecommunicationsSystem (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN(NG RAN), or some other type of RAN. The UEs 1801 and 1802 utilizeconnections 1803 and 1804, respectively, each of which comprises aphysical communications interface or layer (discussed in further detailbelow); in this example, the connections 1803 and 1804 are illustratedas an air interface to enable communicative coupling, and can beconsistent with cellular communications protocols, such as a GlobalSystem for Mobile Communications (GSM) protocol, a code-divisionmultiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol,a PTT over Cellular (POC) protocol, a Universal MobileTelecommunications System (UMTS) protocol, a 3GPP Long Term Evolution(LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR)protocol, and the like.

In this embodiment, the UEs 1801 and 1802 may further directly exchangecommunication data via a ProSe interface 1805. The ProSe interface 1805may alternatively be referred to as a sidelink interface comprising oneor more logical channels, including but not limited to a PhysicalSidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel(PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a PhysicalSidelink Broadcast Channel (PSBCH).

The UE 1802 is shown to be configured to access an access point (AP)1806 via connection 1807. The connection 1807 can comprise a localwireless connection, such as a connection consistent with any IEEE802.11 protocol, wherein the AP 1806 would comprise a wireless fidelity(WiFi®) router. In this example, the AP 1806 may be connected to theInternet without connecting to the core network of the wireless system(described in further detail below).

The RAN 1810 can include one or more access nodes that enable theconnections 1803 and 1804. These access nodes (ANs) can be referred toas base stations (BSs), NodeBs, evolved NodeBs (eNBs), next GenerationNodeBs (gNB), RAN nodes, and so forth, and can comprise ground stations(e.g., terrestrial access points) or satellite stations providingcoverage within a geographic area (e.g., a cell). The RAN 1810 mayinclude one or more RAN nodes for providing macrocells, e.g., macro RANnode 1811, and one or more RAN nodes for providing femtocells orpicocells (e.g., cells having smaller coverage areas, smaller usercapacity, or higher bandwidth compared to macrocells), e.g., low power(LP) RAN node 1812.

Any of the RAN nodes 1811 and 1812 can terminate the air interfaceprotocol and can be the first point of contact for the UEs 1801 and1802. In some embodiments, any of the RAN nodes 1811 and 1812 canfulfill various logical functions for the RAN 1810 including, but notlimited to, radio network controller (RNC) functions such as radiobearer management, uplink and downlink dynamic radio resource managementand data packet scheduling, and mobility management.

In accordance with some embodiments, the UEs 1801 and 1802 can beconfigured to communicate using Orthogonal Frequency-DivisionMultiplexing (OFDM) communication signals with each other or with any ofthe RAN nodes 1811 and 1812 over a multicarrier communication channel inaccordance various communication techniques, such as, but not limitedto, an Orthogonal Frequency-Division Multiple Access (OFDMA)communication technique (e.g., for downlink communications) or a SingleCarrier Frequency Division Multiple Access (SC-FDMA) communicationtechnique (e.g., for uplink and ProSe or sidelink communications),although the scope of the embodiments is not limited in this respect.The OFDM signals can comprise a plurality of orthogonal subcarriers.

In some embodiments, a downlink resource grid can be used for downlinktransmissions from any of the RAN nodes 1811 and 1812 to the UEs 1801and 1802, while uplink transmissions can utilize similar techniques. Thegrid can be a time-frequency grid, called a resource grid ortime-frequency resource grid, which is the physical resource in thedownlink in each slot. Such a time-frequency plane representation is acommon practice for OFDM systems, which makes it intuitive for radioresource allocation. Each column and each row of the resource gridcorresponds to one OFDM symbol and one OFDM subcarrier, respectively.The duration of the resource grid in the time domain corresponds to oneslot in a radio frame. The smallest time-frequency unit in a resourcegrid is denoted as a resource element. Each resource grid comprises anumber of resource blocks, which describe the mapping of certainphysical channels to resource elements. Each resource block comprises acollection of resource elements; in the frequency domain, this mayrepresent the smallest quantity of resources that currently can beallocated. There are several different physical downlink channels thatare conveyed using such resource blocks.

The physical downlink shared channel (PDSCH) may carry user data andhigher-layer signaling to the UEs 1801 and 1802. The physical downlinkcontrol channel (PDCCH) may carry information about the transport formatand resource allocations related to the PDSCH channel, among otherthings. It may also inform the UEs 1801 and 1802 about the transportformat, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request)information related to the uplink shared channel. Typically, downlinkscheduling (assigning control and shared channel resource blocks to theUE 1802 within a cell) may be performed at any of the RAN nodes 1811 and1812 based on channel quality information fed back from any of the UEs1801 and 1802. The downlink resource assignment information may be senton the PDCCH used for (e.g., assigned to) each of the UEs 1801 and 1802.

The PDCCH may use control channel elements (CCEs) to convey the controlinformation. Before being mapped to resource elements, the PDCCHcomplex-valued symbols may first be organized into quadruplets, whichmay then be permuted using a sub-block interleaver for rate matching.Each PDCCH may be transmitted using one or more of these CCEs, whereeach CCE may correspond to nine sets of four physical resource elementsknown as resource element groups (REGs). Four Quadrature Phase ShiftKeying (QPSK) symbols may be mapped to each REG. The PDCCH can betransmitted using one or more CCEs, depending on the size of thedownlink control information (DCI) and the channel condition. There canbe four or more different PDCCH formats defined in LTE with differentnumbers of CCEs (e.g., aggregation level, L=1, 2, 4, or 8).

Some embodiments may use concepts for resource allocation for controlchannel information that are an extension of the above-describedconcepts. For example, some embodiments may utilize an enhanced physicaldownlink control channel (EPDCCH) that uses PDSCH resources for controlinformation transmission. The EPDCCH may be transmitted using one ormore enhanced the control channel elements (ECCEs). Similar to above,each ECCE may correspond to nine sets of four physical resource elementsknown as enhanced resource element groups (EREGs). An ECCE may haveother numbers of EREGs in some situations.

The RAN 1810 is shown to be communicatively coupled to a core network(CN) 1820—via an S1 interface 1813. In embodiments, the CN 1820 may bean evolved packet core (EPC) network, a NextGen Packet Core (NPC)network, or some other type of CN. In this embodiment the S1 interface1813 is split into two parts: the S1-U interface 1814, which carriestraffic data between the RAN nodes 1811 and 1812 and a serving gateway(S-GW) 1822, and an S1-mobility management entity (MME) interface 1815,which is a signaling interface between the RAN nodes 1811 and 1812 andMMEs 1821.

In this embodiment, the CN 1820 comprises the MMEs 1821, the S-GW 1822,a Packet Data Network (PDN) Gateway (P-GW) 1823, and a home subscriberserver (HSS) 1824. The MMEs 1821 may be similar in function to thecontrol plane of legacy Serving General Packet Radio Service (GPRS)Support Nodes (SGSN). The MMEs 1821 may manage mobility aspects inaccess such as gateway selection and tracking area list management. TheHSS 1824 may comprise a database for network users, includingsubscription-related information to support the network entities'handling of communication sessions. The CN 1820 may comprise one orseveral HSSs 1824, depending on the number of mobile subscribers, on thecapacity of the equipment, on the organization of the network, etc. Forexample, the HSS 1824 can provide support for routing/roaming,authentication, authorization, naming/addressing resolution, locationdependencies, etc.

The S-GW 1822 may terminate the S1 interface 1813 towards the RAN 1810,and routes data packets between the RAN 1810 and the CN 1820. Inaddition, the S-GW 1822 may be a local mobility anchor point forinter-RAN node handovers and also may provide an anchor for inter-3GPPmobility. Other responsibilities may include lawful intercept, charging,and some policy enforcement.

The P-GW 1823 may terminate an SGi interface toward a PDN. The P-GW 1823may route data packets between the CN 1820 (e.g., an EPC network) andexternal networks such as a network including the application server1830 (alternatively referred to as application function (AF)) via anInternet Protocol (IP) interface 1825. Generally, an application server1830 may be an element offering applications that use IP bearerresources with the core network (e.g., UMTS Packet Services (PS) domain,LTE PS data services, etc.). In this embodiment, the P-GW 1823 is shownto be communicatively coupled to an application server 1830 via an IPcommunications interface 1825. The application server 1830 can also beconfigured to support one or more communication services (e.g.,Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, groupcommunication sessions, social networking services, etc.) for the UEs1801 and 1802 via the CN 1820.

The P-GW 1823 may further be a node for policy enforcement and chargingdata collection. A Policy and Charging Enforcement Function (PCRF) 1826is the policy and charging control element of the CN 1820. In anon-roaming scenario, there may be a single PCRF in the Home Public LandMobile Network (HPLMN) associated with a UE's Internet ProtocolConnectivity Access Network (IP-CAN) session. In a roaming scenario withlocal breakout of traffic, there may be two PCRFs associated with a UE'sIP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF(V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF1826 may be communicatively coupled to the application server 1830 viathe P-GW 1823. The application server 1830 may signal the PCRF 1826 toindicate a new service flow and select the appropriate Quality ofService (QoS) and charging parameters. The PCRF 1826 may provision thisrule into a Policy and Charging Enforcement Function (PCEF) (not shown)with the appropriate traffic flow template (TFT) and QoS class ofidentifier (QCI), which commences the QoS and charging as specified bythe application server 1830.

FIG. 19 illustrates an architecture of a system 1900 of a network inaccordance with some embodiments. The system 1900 is shown to include aUE 1901, which may be the same or similar to UEs 1801 and 1802 discussedpreviously; a RAN node 1911, which may be the same or similar to RANnodes 1811 and 1812 discussed previously; a User Plane Function (UPF)1902; a Data network (DN) 1903, which may be, for example, operatorservices, Internet access or 3rd party services; and a 5G Core Network(5GC or CN) 1920.

The CN 1920 may include an Authentication Server Function (AUSF) 1922; aCore Access and Mobility Management Function (AMF) 1921; a SessionManagement Function (SMF) 1924; a Network Exposure Function (NEF) 1923;a Policy Control Function (PCF) 1926; a Network Function (NF) RepositoryFunction (NRF) 1925; a Unified Data Management (UDM) 1927; and anApplication Function (AF) 1928. The CN 1920 may also include otherelements that are not shown, such as a Structured Data Storage networkfunction (SDSF), an Unstructured Data Storage network function (UDSF),and the like.

The UPF 1902 may act as an anchor point for intra-RAT and inter-RATmobility, an external PDU session point of interconnect to DN 1903, anda branching point to support multi-homed PDU session. The UPF 1902 mayalso perform packet routing and forwarding, packet inspection, enforceuser plane part of policy rules, lawfully intercept packets (UPcollection); traffic usage reporting, perform QoS handling for userplane (e.g. packet filtering, gating, UL/DL rate enforcement), performUplink Traffic verification (e.g., SDF to QoS flow mapping), transportlevel packet marking in the uplink and downlink, and downlink packetbuffering and downlink data notification triggering. UPF 1902 mayinclude an uplink classifier to support routing traffic flows to a datanetwork. The DN 1903 may represent various network operator services,Internet access, or third party services. NY 1903 may include, or besimilar to application server 1830 discussed previously.

The AUSF 1922 may store data for authentication of UE 1901 and handleauthentication related functionality. The AUSF 1922 may facilitate acommon authentication framework for various access types.

The AMF 1921 may be responsible for registration management (e.g., forregistering UE 1901, etc.), connection management, reachabilitymanagement, mobility management, and lawful interception of AMF-relatedevents, and access authentication and authorization. AMF 1921 mayprovide transport for SM messages between and SMF 1924, and act as atransparent proxy for routing SM messages. AMF 1921 may also providetransport for short message service (SMS) messages between UE 1901 andan SMS function (SMSF) (not shown by FIG. 19). AMF 1921 may act asSecurity Anchor Function (SEA), which may include interaction with theAUSF 1922 and the UE 1901, receipt of an intermediate key that wasestablished as a result of the UE 1901 authentication process. WhereUSIM based authentication is used, the AMF 1921 may retrieve thesecurity material from the AUSF 1922. AMF 1921 may also include aSecurity Context Management (SCM) function, which receives a key fromthe SEA that it uses to derive access-network specific keys.Furthermore, A M F 1921 may be a termination point of RAN CP interface(N2 reference point), a termination point of NAS (NI) signaling, andperform NAS ciphering and integrity protection.

AMF 1921 may also support NAS signaling with a UE 1901 over an N3interworking-function (IWF) interface. The N3IWF may be used to provideaccess to untrusted entities. N3IWF may be a termination point for theN2 and N3 interfaces for control plane and user plane, respectively, andas such, may handle N2 signaling from SMF and AMF for PDU sessions andQoS, encapsulate/de-encapsulate packets for IPSec and N3 tunneling, markN3 user-plane packets in the uplink, and enforce QoS corresponding to N3packet marking taking into account QoS requirements associated to suchmarking received over N2. N3IWF may also relay uplink and downlinkcontrol-plane NAS (NI) signaling between the UE 1901 and AMF 1921, andrelay uplink and downlink user-plane packets between the UE 1901 and UPF1902. The N3IWF also provides mechanisms for IPsec tunnel establishmentwith the UE 1901.

The SMF 1924 may be responsible for session management (e.g., sessionestablishment, modify and release, including tunnel maintain between UPFand AN node); UE IP address allocation & management (including optionalAuthorization); Selection and control of UP function; Configures trafficsteering at UPF to route traffic to proper destination; termination ofinterfaces towards Policy control functions; control part of policyenforcement and QoS; lawful intercept (for SM events and interface to LISystem); termination of SM parts of NAS messages; downlink DataNotification; initiator of AN specific SM information, sent via AMF overN2 to AN; determine SSC mode of a session. The SMF 1924 may include thefollowing roaming functionality: handle local enforcement to apply QoSSLAs (VPLMN); charging data collection and charging interface (VPLMN);lawful intercept (in VPLMN for SM events and interface to LI System);support for interaction with external DN for transport of signaling forPDU session authorization/authentication by external DN.

The NEF 1923 may provide means for securely exposing the services andcapabilities provided by 3GPP network functions for third party,internal exposure/re-exposure, Application Functions (e.g., AF 1928),edge computing or fog computing systems, etc. In such embodiments, theNEF 1923 may authenticate, authorize, and/or throttle the AFs. NEF 1923may also translate information exchanged with the AF 1928 andinformation exchanged with internal network functions. For example, theNEF 1923 may translate between an AF-Service-Identifier and an internal5GC information. NEF 1923 may also receive information from othernetwork functions (NFs) based on exposed capabilities of other networkfunctions. This information may be stored at the NEF 1923 as structureddata, or at a data storage NF using a standardized interfaces. Thestored information can then be re-exposed by the NEF 1923 to other NFsand AFs, and/or used for other purposes such as analytics.

The NRF 1925 may support service discovery functions, receive NFDiscovery Requests from NF instances, and provide the information of thediscovered NF instances to the NF instances. NRF 1925 also maintainsinformation of available NF instances and their supported services.

The PCF 1926 may provide policy rules to control plane function(s) toenforce them, and may also support unified policy framework to governnetwork behavior. The PCF 1926 may also implement a front end (FE) toaccess subscription information relevant for policy decisions in a UDRof UDM 1927.

The UDM 1927 may handle subscription-related information to support thenetwork entities' handling of communication sessions, and may storesubscription data of UE 1901. The UDM 1927 may include two parts, anapplication FE and a User Data Repository (UDR). The UDM may include aUDM FE, which is in charge of processing of credentials, locationmanagement, subscription management and so on. Several different frontends may serve the same user in different transactions. The UDM-FEaccesses subscription information stored in the UDR and performsauthentication credential processing; user identification handling;access authorization; registration/mobility management; and subscriptionmanagement. The UDR may interact with PCF 1926. UDM 1927 may alsosupport SMS management, wherein an SMS-FE implements the similarapplication logic as discussed previously.

The AF 1928 may provide application influence on traffic routing, accessto the Network Capability Exposure (NCE), and interact with the policyframework for policy control. The NCE may be a mechanism that allows the5GC and AF 1928 to provide information to each other via NEF 1923, whichmay be used for edge computing implementations. In such implementations,the network operator and third party services may be hosted close to theUE 1901 access point of attachment to achieve an efficient servicedelivery through the reduced end-to-end latency and load on thetransport network. For edge computing implementations, the 5GC mayselect a UPF 1902 close to the UE 1901 and execute traffic steering fromthe UPF 1902 to DN 1903 via the N6 interface. This may be based on theUE subscription data, UE location, and information provided by the AF1928. In this way, the AF 1928 may influence UPF (re)selection andtraffic routing. Based on operator deployment, when AF 1928 isconsidered to be a trusted entity, the network operator may permit AF1928 to interact directly with relevant NFs.

As discussed previously, the CN 1920 may include an SMSF, which may beresponsible for SMS subscription checking and verification, and relayingSM messages to/from the UE 1901 to/from other entities, such as anSMS-GMSC/IWMSC/SMS-router. The SMS may also interact with AMF 1921 andUDM 1927 for notification procedure that the UE 1901 is available forSMS transfer (e.g., set a UE not reachable flag, and notifying UDM 1927when UE 1901 is available for SMS).

The system 1900 may include the following service-based interfaces:Namf: Service-based interface exhibited by AMF; Nsmf: Service-basedinterface exhibited by SMF; Nnef: Service-based interface exhibited byNEF; Npcf: Service-based interface exhibited by PCF; Nudm: Service-basedinterface exhibited by UDM; Naf: Service-based interface exhibited byAF; Nnrf: Service-based interface exhibited by NRF; and Nausf:Service-based interface exhibited by AUSF.

The system 1900 may include the following reference points: N1:Reference point between the UE and the AMF; N2: Reference point betweenthe (R)AN and the AMF; N3: Reference point between the (R)AN and theUPF; N4: Reference point between the SMF and the UPF; and N6: Referencepoint between the UPF and a Data Network. There may be many morereference points and/or service-based interfaces between the NF servicesin the NFs, however, these interfaces and reference points have beenomitted for clarity. For example, an NS reference point may be betweenthe PCF and the AF; an N7 reference point may be between the PCF and theSMF; an N11 reference point between the AMF and SMF; etc. In someembodiments, the CN 1920 may include an Nx interface, which is aninter-CN interface between the MME (e.g., MME 1821) and the AMF 1921 inorder to enable interworking between CN 1920 and CN 1820.

Although not shown by FIG. 19, system 1900 may include multiple RANnodes 1911 wherein an Xn interface is defined between two or more RANnodes 1911 (e.g., gNBs and the like) that connecting to 5GC 1920,between a RAN node 1911 (e.g., gNB) connecting to 5GC 1920 and an eNB(e.g., a RAN node 1811 of FIG. 18), and/or between two eNBs connectingto 5GC 1920.

In some implementations, the Xn interface may include an Xn user plane(Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U mayprovide non-guaranteed delivery of user plane PDUs and support/providedata forwarding and flow control functionality. The Xn-C may providemanagement and error handling functionality, functionality to manage theXn-C interface; mobility support for UE 1901 in a connected mode (e.g.,CM-CONNECTED) including functionality to manage the UE mobility forconnected mode between one or more RAN nodes 1911. The mobility supportmay include context transfer from an old (source) serving RAN node 1911to new (target) serving RAN node 1911; and control of user plane tunnelsbetween old (source) serving RAN node 1911 to new (target) serving RANnode 1911.

A protocol stack of the Xn-U may include a transport network layer builton Internet Protocol (IP) transport layer, and a GTP-U layer on top of aUDP and/or IP layer(s) to carry user plane PDUs. The Xn-C protocol stackmay include an application layer signaling protocol (referred to as XnApplication Protocol (Xn-AP)) and a transport network layer that isbuilt on an SCTP layer. The SCTP layer may be on top of an IP layer. TheSCTP layer provides the guaranteed delivery of application layermessages. In the transport IP layer point-to-point transmission is usedto deliver the signaling PDUs. In other implementations, the Xn-Uprotocol stack and/or the Xn-C protocol stack may be same or similar tothe user plane and/or control plane protocol stack(s) shown anddescribed herein.

FIG. 20 illustrates example components of a device 2000 in accordancewith some embodiments. In some embodiments, the device 2000 may includeapplication circuitry 2002, baseband circuitry 2004, Radio Frequency(RF) circuitry 2006, front-end module (FEM) circuitry 2008, one or moreantennas 2010, and power management circuitry (PMC) 2012 coupledtogether at least as shown. The components of the illustrated device2000 may be included in a UE or a RAN node. In some embodiments, thedevice 2000 may include fewer elements (e.g., a RAN node may not utilizeapplication circuitry 2002, and instead include a processor/controllerto process IP data received from an EPC). In some embodiments, thedevice 2000 may include additional elements such as, for example,memory/storage, display, camera, sensor, or input/output (I/O)interface. In other embodiments, the components described below may beincluded in more than one device (e.g., said circuitries may beseparately included in more than one device for Cloud-RAN (C-RAN)implementations).

The application circuitry 2002 may include one or more applicationprocessors. For example, the application circuitry 2002 may includecircuitry such as, but not limited to, one or more single-core ormulti-core processors. The processor(s) may include any combination ofgeneral-purpose processors and dedicated processors (e.g., graphicsprocessors, application processors, etc.). The processors may be coupledwith or may include memory/storage and may be configured to executeinstructions stored in the memory/storage to enable various applicationsor operating systems to run on the device 2000. In some embodiments,processors of application circuitry 2002 may process IP data packetsreceived from an EPC.

The baseband circuitry 2004 may include circuitry such as, but notlimited to, one or more single-core or multi-core processors. Thebaseband circuitry 2004 may include one or more baseband processors orcontrol logic to process baseband signals received from a receive signalpath of the RF circuitry 2006 and to generate baseband signals for atransmit signal path of the RF circuitry 2006. Baseband processingcircuitry 2004 may interface with the application circuitry 2002 forgeneration and processing of the baseband signals and for controllingoperations of the RF circuitry 2006. For example, in some embodiments,the baseband circuitry 2004 may include a third generation (3G) basebandprocessor 2004A, a fourth generation (4G) baseband processor 2004B, afifth generation (5G) baseband processor 2004C, or other basebandprocessor(s) 2004D for other existing generations, generations indevelopment or to be developed in the future (e.g., second generation(2G), sixth generation (6G), etc.). The baseband circuitry 2004 (e.g.,one or more of baseband processors 2004A-D) may handle various radiocontrol functions that enable communication with one or more radionetworks via the RF circuitry 2006. In other embodiments, some or all ofthe functionality of baseband processors 2004A-D may be included inmodules stored in the memory 2004G and executed via a Central ProcessingUnit (CPU) 2004E. The radio control functions may include, but are notlimited to, signal modulation/demodulation, encoding/decoding, radiofrequency shifting, etc. In some embodiments, modulation/demodulationcircuitry of the baseband circuitry 2004 may include Fast-FourierTransform (FFT), precoding, or constellation mapping/demappingfunctionality. In some embodiments, encoding/decoding circuitry of thebaseband circuitry 2004 may include convolution, tail-bitingconvolution, turbo, Viterbi, or Low Density Parity Check (LDPC)encoder/decoder functionality. Embodiments of modulation/demodulationand encoder/decoder functionality are not limited to these examples andmay include other suitable functionality in other embodiments.

In some embodiments, the baseband circuitry 2004 may include one or moreaudio digital signal processor(s) (DSP) 2004F. The audio DSP(s) 2004Fmay be include elements for compression/decompression and echocancellation and may include other suitable processing elements in otherembodiments. Components of the baseband circuitry may be suitablycombined in a single chip, a single chipset, or disposed on a samecircuit board in some embodiments. In some embodiments, some or all ofthe constituent components of the baseband circuitry 2004 and theapplication circuitry 2002 may be implemented together such as, forexample, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 2004 may provide forcommunication compatible with one or more radio technologies. Forexample, in some embodiments, the baseband circuitry 2004 may supportcommunication with an evolved universal terrestrial radio access network(EUTRAN) or other wireless metropolitan area networks (WMAN), a wirelesslocal area network (WLAN), or a wireless personal area network (WPAN).Embodiments in which the baseband circuitry 2004 is configured tosupport radio communications of more than one wireless protocol may bereferred to as multi-mode baseband circuitry.

RF circuitry 2006 may enable communication with wireless networks usingmodulated electromagnetic radiation through a non-solid medium. Invarious embodiments, the RF circuitry 2006 may include switches,filters, amplifiers, etc. to facilitate the communication with thewireless network. The RF circuitry 2006 may include a receive signalpath which may include circuitry to down-convert RF signals receivedfrom the FEM circuitry 2008 and provide baseband signals to the basebandcircuitry 2004. RF circuitry 2006 may also include a transmit signalpath which may include circuitry to up-convert baseband signals providedby the baseband circuitry 2004 and provide RF output signals to the FEMcircuitry 2008 for transmission.

In some embodiments, the receive signal path of the RF circuitry 2006may include mixer circuitry 2006A, amplifier circuitry 2006B and filtercircuitry 2006C. In some embodiments, the transmit signal path of the RFcircuitry 2006 may include filter circuitry 2006C and mixer circuitry2006A. RF circuitry 2006 may also include synthesizer circuitry 2006Dfor synthesizing a frequency for use by the mixer circuitry 2006A of thereceive signal path and the transmit signal path. In some embodiments,the mixer circuitry 2006A of the receive signal path may be configuredto down-convert RF signals received from the FEM circuitry 2008 based onthe synthesized frequency provided by synthesizer circuitry 2006D. Theamplifier circuitry 2006B may be configured to amplify thedown-converted signals and the filter circuitry 2006C may be a low-passfilter (LPF) or band-pass filter (BPF) configured to remove unwantedsignals from the down-converted signals to generate output basebandsignals. Output baseband signals may be provided to the basebandcircuitry 2004 for further processing. In some embodiments, the outputbaseband signals may be zero-frequency baseband signals, although thisis not a requirement. In some embodiments, the mixer circuitry 2006A ofthe receive signal path may comprise passive mixers, although the scopeof the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 2006A of the transmit signalpath may be configured to up-convert input baseband signals based on thesynthesized frequency provided by the synthesizer circuitry 2006D togenerate RF output signals for the FEM circuitry 2008. The basebandsignals may be provided by the baseband circuitry 2004 and may befiltered by the filter circuitry 2006C.

In some embodiments, the mixer circuitry 2006A of the receive signalpath and the mixer circuitry 2006A of the transmit signal path mayinclude two or more mixers and may be arranged for quadraturedownconversion and upconversion, respectively. In some embodiments, themixer circuitry 2006A of the receive signal path and the mixer circuitry2006A of the transmit signal path may include two or more mixers and maybe arranged for image rejection (e.g., Hartley image rejection). In someembodiments, the mixer circuitry 2006A of the receive signal path andthe mixer circuitry 2006A may be arranged for direct downconversion anddirect upconversion, respectively. In some embodiments, the mixercircuitry 2006A of the receive signal path and the mixer circuitry 2006Aof the transmit signal path may be configured for super-heterodyneoperation.

In some embodiments, the output baseband signals and the input basebandsignals may be analog baseband signals, although the scope of theembodiments is not limited in this respect. In some alternateembodiments, the output baseband signals and the input baseband signalsmay be digital baseband signals. In these alternate embodiments, the RFcircuitry 2006 may include analog-to-digital converter (ADC) anddigital-to-analog converter (DAC) circuitry and the baseband circuitry2004 may include a digital baseband interface to communicate with the RFcircuitry 2006.

In some dual-mode embodiments, a separate radio IC circuitry may beprovided for processing signals for each spectrum, although the scope ofthe embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry 2006D may be afractional-N synthesizer or a fractional N/N+1 synthesizer, although thescope of the embodiments is not limited in this respect as other typesof frequency synthesizers may be suitable. For example, synthesizercircuitry 2006D may be a delta-sigma synthesizer, a frequencymultiplier, or a synthesizer comprising a phase-locked loop with afrequency divider.

The synthesizer circuitry 2006D may be configured to synthesize anoutput frequency for use by the mixer circuitry 2006A of the RFcircuitry 2006 based on a frequency input and a divider control input.In some embodiments, the synthesizer circuitry 2006D may be a fractionalN/N+1 synthesizer.

In some embodiments, frequency input may be provided by a voltagecontrolled oscillator (VCO), although that is not a requirement. Dividercontrol input may be provided by either the baseband circuitry 2004 orthe application circuitry 2002 (such as an applications processor)depending on the desired output frequency. In some embodiments, adivider control input (e.g., N) may be determined from a look-up tablebased on a channel indicated by the application circuitry 2002.

Synthesizer circuitry 2006D of the RF circuitry 2006 may include adivider, a delay-locked loop (DLL), a multiplexer and a phaseaccumulator. In some embodiments, the divider may be a dual modulusdivider (DMD) and the phase accumulator may be a digital phaseaccumulator (DPA). In some embodiments, the DMD may be configured todivide the input signal by either N or N+1 (e.g., based on a carry out)to provide a fractional division ratio. In some example embodiments, theDLL may include a set of cascaded, tunable, delay elements, a phasedetector, a charge pump and a D-type flip-flop. In these embodiments,the delay elements may be configured to break a VCO period up into Ndequal packets of phase, where Nd is the number of delay elements in thedelay line. In this way, the DLL provides negative feedback to helpensure that the total delay through the delay line is one VCO cycle.

In some embodiments, the synthesizer circuitry 2006D may be configuredto generate a carrier frequency as the output frequency, while in otherembodiments, the output frequency may be a multiple of the carrierfrequency (e.g., twice the carrier frequency, four times the carrierfrequency) and used in conjunction with quadrature generator and dividercircuitry to generate multiple signals at the carrier frequency withmultiple different phases with respect to each other. In someembodiments, the output frequency may be a LO frequency (fLO). In someembodiments, the RF circuitry 2006 may include an IQ/polar converter.

FEM circuitry 2008 may include a receive signal path which may includecircuitry configured to operate on RF signals received from one or moreantennas 2010, amplify the received signals and provide the amplifiedversions of the received signals to the RF circuitry 2006 for furtherprocessing. The FEM circuitry 2008 may also include a transmit signalpath which may include circuitry configured to amplify signals fortransmission provided by the RF circuitry 2006 for transmission by oneor more of the one or more antennas 2010. In various embodiments, theamplification through the transmit or receive signal paths may be donesolely in the RF circuitry 2006, solely in the FEM circuitry 2008, or inboth the RF circuitry 2006 and the FEM circuitry 2008.

In some embodiments, the FEM circuitry 2008 may include a TX/RX switchto switch between transmit mode and receive mode operation. The FEMcircuitry 2008 may include a receive signal path and a transmit signalpath. The receive signal path of the FEM circuitry 2008 may include anLNA to amplify received RF signals and provide the amplified received RFsignals as an output (e.g., to the RF circuitry 2006). The transmitsignal path of the FEM circuitry 2008 may include a power amplifier (PA)to amplify input RF signals (e.g., provided by the RF circuitry 2006),and one or more filters to generate RF signals for subsequenttransmission (e.g., by one or more of the one or more antennas 2010).

In some embodiments, the PMC 2012 may manage power provided to thebaseband circuitry 2004. In particular, the PMC 2012 may controlpower-source selection, voltage scaling, battery charging, or DC-to-DCconversion. The PMC 2012 may often be included when the device 2000 iscapable of being powered by a battery, for example, when the device 2000is included in a UE. The PMC 2012 may increase the power conversionefficiency while providing desirable implementation size and heatdissipation characteristics.

FIG. 20 shows the PMC 2012 coupled only with the baseband circuitry2004. However, in other embodiments, the PMC 2012 may be additionally oralternatively coupled with, and perform similar power managementoperations for, other components such as, but not limited to, theapplication circuitry 2002, the RF circuitry 2006, or the FEM circuitry2008.

In some embodiments, the PMC 2012 may control, or otherwise be part of,various power saving mechanisms of the device 2000. For example, if thedevice 2000 is in an RRC_Connected state, where it is still connected tothe RAN node as it expects to receive traffic shortly, then it may entera state known as Discontinuous Reception Mode (DRX) after a period ofinactivity. During this state, the device 2000 may power down for briefintervals of time and thus save power.

If there is no data traffic activity for an extended period of time,then the device 2000 may transition off to an RRC_Idle state, where itdisconnects from the network and does not perform operations such aschannel quality feedback, handover, etc. The device 2000 goes into avery low power state and it performs paging where again it periodicallywakes up to listen to the network and then powers down again. The device2000 may not receive data in this state, and in order to receive data,it transitions back to an RRC_Connected state.

An additional power saving mode may allow a device to be unavailable tothe network for periods longer than a paging interval (ranging fromseconds to a few hours). During this time, the device is totallyunreachable to the network and may power down completely. Any data sentduring this time incurs a large delay and it is assumed the delay isacceptable.

Processors of the application circuitry 2002 and processors of thebaseband circuitry 2004 may be used to execute elements of one or moreinstances of a protocol stack. For example, processors of the basebandcircuitry 2004, alone or in combination, may be used to execute Layer 3,Layer 2, or Layer 1 functionality, while processors of the applicationcircuitry 2002 may utilize data (e.g., packet data) received from theselayers and further execute Layer 4 functionality (e.g., transmissioncommunication protocol (TCP) and user datagram protocol (UDP) layers).As referred to herein, Layer 3 may comprise a radio resource control(RRC) layer, described in further detail below. As referred to herein,Layer 2 may comprise a medium access control (MAC) layer, a radio linkcontrol (RLC) layer, and a packet data convergence protocol (PDCP)layer, described in further detail below. As referred to herein, Layer 1may comprise a physical (PHY) layer of a UE/RAN node, described infurther detail below.

FIG. 21 illustrates example interfaces of baseband circuitry inaccordance with some embodiments. As discussed above, the basebandcircuitry 2004 of FIG. 20 may comprise processors 2004A-2004E and amemory 2004G utilized by said processors. Each of the processors2004A-2004E may include a memory interface, 2104A-2104E, respectively,to send/receive data to/from the memory 2004G.

The baseband circuitry 2004 may further include one or more interfacesto communicatively couple to other circuitries/devices, such as a memoryinterface 2112 (e.g., an interface to send/receive data to/from memoryexternal to the baseband circuitry 2004), an application circuitryinterface 2114 (e.g., an interface to send/receive data to/from theapplication circuitry 2002 of FIG. 20), an RF circuitry interface 2116(e.g., an interface to send/receive data to/from RF circuitry 2006 ofFIG. 20), a wireless hardware connectivity interface 2118 (e.g., aninterface to send/receive data to/from Near Field Communication (NFC)components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi®components, and other communication components), and a power managementinterface 2120 (e.g., an interface to send/receive power or controlsignals to/from the PMC 2012.

FIG. 22 is an illustration of a control plane protocol stack inaccordance with some embodiments. In this embodiment, a control plane2200 is shown as a communications protocol stack between the UE 1801 (oralternatively, the UE 1802), the RAN node 1811 (or alternatively, theRAN node 1812), and the MME 1821.

A PHY layer 2201 may transmit or receive information used by the MAClayer 2202 over one or more air interfaces. The PHY layer 2201 mayfurther perform link adaptation or adaptive modulation and coding (AMC),power control, cell search (e.g., for initial synchronization andhandover purposes), and other measurements used by higher layers, suchas an RRC layer 2205. The PHY layer 2201 may still further perform errordetection on the transport channels, forward error correction (FEC)coding/decoding of the transport channels, modulation/demodulation ofphysical channels, interleaving, rate matching, mapping onto physicalchannels, and Multiple Input Multiple Output (MIMO) antenna processing.

The MAC layer 2202 may perform mapping between logical channels andtransport channels, multiplexing of MAC service data units (SDUs) fromone or more logical channels onto transport blocks (TB) to be deliveredto PHY via transport channels, de-multiplexing MAC SDUs to one or morelogical channels from transport blocks (TB) delivered from the PHY viatransport channels, multiplexing MAC SDUs onto TBs, schedulinginformation reporting, error correction through hybrid automatic repeatrequest (HARQ), and logical channel prioritization.

An RLC layer 2203 may operate in a plurality of modes of operation,including: Transparent Mode (TM), Unacknowledged Mode (UM), andAcknowledged Mode (AM). The RLC layer 2203 may execute transfer of upperlayer protocol data units (PDUs), error correction through automaticrepeat request (ARQ) for AM data transfers, and concatenation,segmentation and reassembly of RLC SDUs for UM and AM data transfers.The RLC layer 2203 may also execute re-segmentation of RLC data PDUs forAM data transfers, reorder RLC data PDUs for UM and AM data transfers,detect duplicate data for UM and AM data transfers, discard RLC SDUs forUM and AM data transfers, detect protocol errors for AM data transfers,and perform RLC re-establishment.

A PDCP layer 2204 may execute header compression and decompression of IPdata, maintain PDCP Sequence Numbers (SNs), perform in-sequence deliveryof upper layer PDUs at re-establishment of lower layers, eliminateduplicates of lower layer SDUs at re-establishment of lower layers forradio bearers mapped on RLC AM, cipher and decipher control plane data,perform integrity protection and integrity verification of control planedata, control timer-based discard of data, and perform securityoperations (e.g., ciphering, deciphering, integrity protection,integrity verification, etc.).

The main services and functions of the RRC layer 2205 may includebroadcast of system information (e.g., included in Master InformationBlocks (MIBs) or System Information Blocks (SIBs) related to thenon-access stratum (NAS)), broadcast of system information related tothe access stratum (AS), paging, establishment, maintenance and releaseof an RRC connection between the UE and E-UTRAN (e.g., RRC connectionpaging, RRC connection establishment, RRC connection modification, andRRC connection release), establishment, configuration, maintenance andrelease of point-to-point radio bearers, security functions includingkey management, inter radio access technology (RAT) mobility, andmeasurement configuration for UE measurement reporting. Said MIBs andSIBs may comprise one or more information elements (IEs), which may eachcomprise individual data fields or data structures.

The UE 1801 and the RAN node 1811 may utilize a Uu interface (e.g., anLTE-Uu interface) to exchange control plane data via a protocol stackcomprising the PHY layer 2201, the MAC layer 2202, the RLC layer 2203,the PDCP layer 2204, and the RRC layer 2205.

In the embodiment shown, the non-access stratum (NAS) protocols 2206form the highest stratum of the control plane between the UE 1801 andthe MME 1821. The NAS protocols 2206 support the mobility of the UE 1801and the session management procedures to establish and maintain IPconnectivity between the UE 1801 and the P-GW 1823.

The S1 Application Protocol (S1-AP) layer 2215 may support the functionsof the S1 interface and comprise Elementary Procedures (EPs). An EP is aunit of interaction between the RAN node 1811 and the CN 1820. The S1-APlayer services may comprise two groups: UE-associated services and nonUE-associated services. These services perform functions including, butnot limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UEcapability indication, mobility, NAS signaling transport, RANInformation Management (RIM), and configuration transfer.

The Stream Control Transmission Protocol (SCTP) layer (alternativelyreferred to as the stream control transmission protocol/internetprotocol (SCTP/IP) layer) 2214 may ensure reliable delivery of signalingmessages between the RAN node 1811 and the MME 1821 based, in part, onthe IP protocol, supported by an IP layer 2213. An L2 layer 2212 and anL1 layer 2211 may refer to communication links (e.g., wired or wireless)used by the RAN node and the MME to exchange information.

The RAN node 1811 and the MME 1821 may utilize an S1-MME interface toexchange control plane data via a protocol stack comprising the L1 layer2211, the L2 layer 2212, the IP layer 2213, the SCTP layer 2214, and theS1-AP layer 2215.

FIG. 23 is an illustration of a user plane protocol stack in accordancewith some embodiments. In this embodiment, a user plane 2300 is shown asa communications protocol stack between the UE 1801 (or alternatively,the UE 1802), the RAN node 1811 (or alternatively, the RAN node 1812),the S-GW 1822, and the P-GW 1823. The user plane 2300 may utilize atleast some of the same protocol layers as the control plane 2200. Forexample, the UE 1801 and the RAN node 1811 may utilize a Uu interface(e.g., an LTE-Uu interface) to exchange user plane data via a protocolstack comprising the PHY layer 2201, the MAC layer 2202, the RLC layer2203, the PDCP layer 2204.

The General Packet Radio Service (GPRS) Tunneling Protocol for the userplane (GTP-U) layer 2304 may be used for carrying user data within theGPRS core network and between the radio access network and the corenetwork. The user data transported can be packets in any of IPv4, IPv6,or PPP formats, for example. The UDP and IP security (UDP/IP) layer 2303may provide checksums for data integrity, port numbers for addressingdifferent functions at the source and destination, and encryption andauthentication on the selected data flows. The RAN node 1811 and theS-GW 1822 may utilize an S1-U interface to exchange user plane data viaa protocol stack comprising the L1 layer 2211, the L2 layer 2212, theUDP/IP layer 2303, and the GTP-U layer 2304. The S-GW 1822 and the P-GW1823 may utilize an S5/S8a interface to exchange user plane data via aprotocol stack comprising the L1 layer 2211, the L2 layer 2212, theUDP/IP layer 2303, and the GTP-U layer 2304. As discussed above withrespect to FIG. 22, NAS protocols support the mobility of the UE 1801and the session management procedures to establish and maintain IPconnectivity between the UE 1801 and the P-GW 1823.

FIG. 24 illustrates components of a core network in accordance with someembodiments. The components of the CN 1820 may be implemented in onephysical node or separate physical nodes including components to readand execute instructions from a machine-readable or computer-readablemedium (e.g., a non-transitory machine-readable storage medium). In someembodiments, Network Functions Virtualization (NFV) is utilized tovirtualize any or all of the above described network node functions viaexecutable instructions stored in one or more computer readable storagemediums (described in further detail below). A logical instantiation ofthe CN 1820 may be referred to as a network slice 2401. A logicalinstantiation of a portion of the CN 1820 may be referred to as anetwork sub-slice 2402 (e.g., the network sub-slice 2402 is shown toinclude the PGW 1823 and the PCRF 1826).

NFV architectures and infrastructures may be used to virtualize one ormore network functions, alternatively performed by proprietary hardware,onto physical resources comprising a combination of industry-standardserver hardware, storage hardware, or switches. In other words, NFVsystems can be used to execute virtual or reconfigurable implementationsof one or more EPC components/functions.

FIG. 25 is a block diagram illustrating components, according to someexample embodiments, able to read instructions from a machine-readableor computer-readable medium (e.g., a non-transitory machine-readablestorage medium) and perform any one or more of the methodologiesdiscussed herein. Specifically, FIG. 25 shows a diagrammaticrepresentation of hardware resources 2500 including one or moreprocessors (or processor cores) 2510, one or more memory/storage devices2520, and one or more communication resources 2530, each of which may becommunicatively coupled via a bus 2540. For embodiments where nodevirtualization (e.g., NFV) is utilized, a hypervisor 2502 may beexecuted to provide an execution environment for one or more networkslices/sub-slices to utilize the hardware resources 2500.

The processors 2510 (e.g., a central processing unit (CPU), a reducedinstruction set computing (RISC) processor, a complex instruction setcomputing (CISC) processor, a graphics processing unit (GPU), a digitalsignal processor (DSP) such as a baseband processor, an applicationspecific integrated circuit (ASIC), a radio-frequency integrated circuit(RFIC), another processor, or any suitable combination thereof) mayinclude, for example, a processor 2512 and a processor 2514.

The memory/storage devices 2520 may include main memory, disk storage,or any suitable combination thereof. The memory/storage devices 2520 mayinclude, but are not limited to any type of volatile or non-volatilememory such as dynamic random access memory (DRAM), static random-accessmemory (SRAM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), Flashmemory, solid-state storage, etc.

The communication resources 2530 may include interconnection or networkinterface components or other suitable devices to communicate with oneor more peripheral devices 2504 or one or more databases 2506 via anetwork 2508. For example, the communication resources 2530 may includewired communication components (e.g., for coupling via a UniversalSerial Bus (USB)), cellular communication components, NFC components,Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components,and other communication components.

Instructions 2550 may comprise software, a program, an application, anapplet, an app, or other executable code for causing at least any of theprocessors 2510 to perform any one or more of the methodologiesdiscussed herein. The instructions 2550 may reside, completely orpartially, within at least one of the processors 2510 (e.g., within theprocessor's cache memory), the memory/storage devices 2520, or anysuitable combination thereof. Furthermore, any portion of theinstructions 2550 may be transferred to the hardware resources 2500 fromany combination of the peripheral devices 2504 or the databases 2506.Accordingly, the memory of processors 2510, the memory/storage devices2520, the peripheral devices 2504, and the databases 2506 are examplesof computer-readable and machine-readable media.

The foregoing description of one or more implementations providesillustration and description, but is not intended to be exhaustive or tolimit the scope of embodiments to the precise form disclosed.Modifications and variations are possible in light of the aboveteachings or may be acquired from practice of various embodiments.

The invention claimed is:
 1. An apparatus for a user equipment (UE),comprising: a memory interface to send or receive, to or from a datastorage device, delay budget information (DBI) for DBI signaling betweena remote UE and the UE, the UE configured to receive one or more mediastreams from the remote UE; and one or more processors to: based onradio access network (RAN) delay budget reporting and a determination ofgood radio conditions at the UE, reduce an air interface delay of the UEto receive the one or more media streams from the remote UE; in responseto a reduction in the air interface delay of the UE, generate a realtime transport protocol (RTCP) feedback message comprising the DBI forthe remote UE, the RTCP feedback message comprising an indication of anavailable delay budget to the remote UE; and decode a query message fromthe remote UE, the query message to request additional delay budget fromthe UE, wherein the one or more processors are configured to decode,during real time transfer protocol (RTP) streaming of the one or moremedia streams, a query message from the remote UE to request additionaldelay budget from the UE, the query message comprising an RTCP feedbackmessage type to carry the requested additional delay budget.
 2. Theapparatus of claim 1, wherein the UE is configured as a multimediatelephony service for internet protocol multimedia subsystem (MTSI)client, and wherein the UE is configured as an MTSI receiver and theremote UE is configured as an MTSI sender.
 3. The apparatus of claim 1,wherein the RTCP feedback message comprises feedback control information(FCI) including an additional delay parameter, and a sign parameter forthe additional delay parameter.
 4. The apparatus of claim 3, wherein theadditional delay parameter comprises sixteen bits and indicates anavailable additional delay budget value in milliseconds.
 5. Theapparatus of claim 3, wherein the sign parameter comprises a Booleanparameter configured to indicate whether the additional delay parameteris a positive value to add delay budget or a negative value to reducethe delay budget.
 6. The apparatus of claim 1, wherein the FCI furtherincludes a Boolean query parameter for additional delay budget, theBoolean query parameter set to 1 to indicate that the RTCP feedbackmessage is sent from the UE to the remote UE to indicate the availabledelay budget to the remote UE, or or set to 0 to indicate that the RTCPfeedback message is received by the UE from the remote UE to requestadditional delay budget availability.
 7. An apparatus for multimediatelephony service for internet protocol multimedia subsystem (MTSI)client, the MTSI client configured as an MTSI sender, the apparatuscomprising: a memory interface to send or receive, to or from a datastorage device, delay budget information (DBI) for DBI signaling; andone or more processors to: decode a first real time transport protocol(RTCP) feedback message comprising the DBI from an MTSI receiver, theRTCP feedback message comprising an indication of an available delaybudget for the MTSI sender; generate a query to a wireless network nodefor additional delay budget based on the indication of the availabledelay budget from the MTSI receiver, the indication of available delaybudget in response to a determination of good radio conditions at theMTSI receiver and a reduction in the air interface delay at the MTSIreceiver by the MTSI receiver; process an indication from the wirelessnetwork node that the additional delay budget is granted; and inresponse to the indication from the wireless network node that theadditional delay budget is granted, use the additional delay budget tosend to the MTSI receiver, wherein the one or more processors arefurther configured to generate a second RTCP feedback message to requestadditional delay budget from the MTSI receiver during real time transferprotocol (RTP) streaming of the media stream.
 8. The apparatus of claim7, wherein the one or more processors are further configured todetermine, based on the indication of the available delay budget in thefirst RTCP feedback message, an amount of the additional delay budget torequest from the wireless network node over a radio access network (RAN)interface.
 9. The apparatus of claim 7, wherein the second RTCP feedbackmessage comprises feedback control information (FCI) including anadditional delay parameter, a sign parameter for the additional delayparameter, and a Boolean query parameter for additional delay budget.10. The apparatus of claim 9, wherein the Boolean query parameter is setto 1 to indicate that the second RTCP feedback message is sent from theMTSI sender to the MTSI receiver to request additional delay budget. 11.The apparatus of claim 9, wherein the additional delay parametercomprises sixteen bits and indicates an available additional delaybudget value in milliseconds.
 12. The apparatus of claim 9, wherein thesign parameter comprises a Boolean parameter configured to indicatewhether the additional delay parameter is a positive value to add delaybudget or a negative value to reduce the delay budget.
 13. The apparatusof claim 7, wherein the one or more processors are further configured togenerate a session description protocol (SDP) offer message, the SDPoffer message configured to indicate to the MTSI receiver that the MTSIsender supports the DBI signaling.
 14. The apparatus of claim 7, whereinthe one or more processors are further configured to decode a sessiondescription protocol (SDP) offer message received from the MTSIreceiver, the SDP offer message configured to indicate that the MTSIreceiver supports the DBI signaling.